Types of computer viruses
What are the major types of computer viruses? What do we mean when we say computer virus? How do we secure our data and information and prevent continuously from the possible virus or malware attack? We will try to answer these questions in this article.
Usually people refer all these destructive programs as a virus; however, there are other software programs such as spyware and Trojans capable of destroying data from a computer.
Here are the essentials we should be aware of about computer virus and its prevention methods.
But first let us answer this question:-
What is a computer virus?
To put it simply, computer virus is a computer program capable of attaching itself to a disk, file or program. It then replicates itself. This happens without the knowledge of a user.
A virus can infect and damage computer systems and files. Virus has several behaviors or variants. Variant is a modified version of a virus, usually difficult to remove it like the original one. Some virus resides in a computer’s memory and triggers when a program or file loads. And other type of virus will fill a computer with annoying messages.
Other types of computer viruses
Worms are the other destructive parasitic computer program which like a virus replicates itself. This virus copies itself on the same computer and sends copies to other computers via a network.
Worms can easily transfer through an email that comes with attachment. The attachments may have .exe, .scr, .zip extensions. You need to beware of those kinds of attachments. If it is opened, it executes itself and spread throughout a computer and entire network.
Worms are responsible for sluggish computer, it fills the computer memory until it fills and there won’t be enough space to open file or load programs.
Trojan horse is another program which behaves as if it is a useful application but it performs something the user doesn’t expect. Trojan doesn’t replicate itself. Trojans are used to steal passwords and logon details, usually from bank customers to gain access to their credit card information and other confidential data.
Spyware is also a type of software capable of infecting computer systems the same way as a virus. The purpose of spyware is to send information (such as identity theft) from your computer to the creator. Most anti-virus programs include anti-spyware application.
Keyboard loggers is a kind of code which monitor the key pressed on a keyboard and send this information back to the author. It is used to steal password and other information.
How viruses enter a computer system?
Definitely, a virus enters into a computer system from outside.
Here are the ways that open a door for system infection.
- Email attachments
- External devices such as portable hard disk, flash memory, floppy disk
- Internet downloads
- Cracked or pirated software
How to prevent virus attack?
The following are good practices to protect your computer from viruses. It helps to guard your computer from all types of computer viruses.
- Install anti-virus programs and update on regular basis. Most anti-virus applications have daily, weekly and monthly update definitions.
- Try to reduce using external disks, specially other people’s disk
- Don’t open e-mails with attachments from unknown sender. Even you should take care if you receive it from one of the mail lists.
- Do not download programs from sites you don’t know and trust - Always scan any external disks before copying or installing from them
- Always backup your files to other medias
- Be alert for new threats and protection methods
List of some of the most popular anti-virus programs
If updated regularly almost all types of computer viruses can be removed using the following anti-virus programs.
- Symantec Anti-virus
- McAfee Virus scan
- Kaspersky Anti-virus
- Avira Anti-virus
- Avast Anti-virus
- AVG Anti-virus
- Panda Anti-virus
- F-secure
- eScan (recently developed anti-virus)
Conclusion
So far we have tried to discuss the types of computer viruses and the effect they pose on computer systems. We also saw the preventive measures we should take to secure digital data from possible virus attack.
I believe you have got some helpful information about computer virus from this article.
How to remove virus from computer?
After taking the necessary steps of protecting your computer from virus, it still gets infected by a virus. Mostly, if you use internet very often the chances of having a virus in your computer will increase. If your computer gets caught by virus, automatically you should remove it using the best anti-virus program.
Actually, no anti-virus program guards 100% your system from possible virus attack. But you will reduce the risk by 95% and even more depending on the quality of anti-virus program.
However, what will you do about a virus that is recognized by anti-virus program but won’t be removed or deleted? I often encountered with such kind of virus. But I easily managed to remove virus from computer using the technique mentioned in this article. It is the best way to get rid of computer virus - almost completely.
If you are into such kind of situation, below are the steps you should go through:-
Step 1
Install Anti-virus program and update its definition
Don’t have an anti-virus program installed on your computer, you should install now. If you already have one, make sure it is updated with the latest definitions. Regarding anti-virus programs, several types of anti-virus programs are available on the market. You may spend a little to get the best anti-virus that can access any type of virus; if you can’t afford to buy you can get free versions.
Anti-virus programs such as Avast, Avira, AVG have free versions which can be downloaded directly from their site. These versions luck some of the features found in the commercial anti-virus products.
Step 2
The next step to remove virus from computer is to Turn off your computer restore point and restart the computer in SAFE MODE
What is system restore?
“System restore is a component of Windows XP Professional that you can use to restore your computer to a previous state, if a problem occurs, without losing your personal data files (such as Microsoft Word documents, browsing history, drawings, favorites, or e-mail).” Source: Microsoft Help and Support Center
In Windows XP computer, to turn off System Restore, Click on Start--->Control Panel and Open System. System Properties dialogue box will open. Click on System Restore tab and CHECK the box beside “Turn off System Restore on all drives” label or can only turn off the drive of your choice. But it must be your root drive.
system properties
system restore
Step 3
Restarting your computer in SAFE MODE is the next step to remove virus from computer.
In Safe Mode, a computer system loads with basic files and drivers that are important for running your computer. This will help to keep some programs and services disabled. And these are the places that easily get infected by a virus.
In Safe Mode the virus will remain dormant since most of the nonessential programs are inactive.
To start your computer in SAFE MODE, reboot your computer and while rebooting keep PRESSING F8 Key before the Windows Logo come. Windows advanced options menu will appear, like you see below.
windows_option_menu
Using Arrow Key, choose SAFE MODE from the menu and Press Enter. Windows will log in after listing a series line of text. You will see SAFE MODE at the four corners of the screen which tells that your computer is now in SAFE MODE.
Step 4
Finally, you should fully scan your computer with the anti-virus program. In addition, in order to remove any kind of malicious code effectively you may use additional Spyware, Malwares, Adware, Trojans removal tools.
After cleaning your computer from viruses, restart your computer and TURN ON SYSTEM RESTORE. Now, you have a virus free computer.
Conclusion
These are the steps all you need to remove virus from computer completely. However, as new viruses are emerges every day, you should always insure that the anti-virus program installed is updated with latest definitions.
In addition, always be vigilant about new threats. The anti-virus programmers will develop a cure for the new virus, till then it may get into your system and damage your data.
Free computer virus cleaner
Whether you use free computer virus cleaner or the commercial virus remover, installing an anti-virus program is one of the requirements for healthy computer. Anti-virus program is a kind of software specifically designed for protecting your computer from all types of computer viruses and dangerous codes.
In simple terms, computer virus is a malicious program that can damage and delete any type of file saved on a computer disk. It is even capable of damaging the whole computer system settings. Currently, several types of viruses, Trojans, worms, key loggers, spywares, adware, dialers, rootkits exist. In addition, every day new malwares are released by unscrupulous individuals. These malwares are either new or modified version of existing virus type, but very powerful comparing to earlier type of viruses.
So, what is the solution?
In order to protect your digital data, presently two types of anti-virus programs are available – free and commercial (paid) version. This article is about free computer virus cleaner.
When we talk about free AV programs our choice is limited only on those vendors who offer AV programs freely. Unfortunately, there are few vendors who give away free version of AV programs.
Below you will find the top free anti-virus programs you find on the net. Which one is NUMBER ONE? Well, that is difficult question to answer since the strength of each AV program is different. But you will still find ranking among free AV programs. The problem of the ranking is that they have different standings on several sites.So, it is better to put the available top free versions here.
Criteria to choose free computer virus cleaner
- Ability to detect all types of malwares
- Capability of scanning e-mails, WebPages and real-time protection
- Effectiveness to remove a virus
- Frequency of update definition availability
- Low usage of computer resources
- Ease of installation
Disadvantages of free computer virus cleaner
- Comparing to commercial version, the level of free AV protection is very limited
- All the features we often find in commercial versions are not included in the free versions
- The rate of the update definition is limited
- Program update is not available for free versions
- Only for single computer use
When to use free anti-virus programs
- If you do not use your computer to connect to internet. These days the most dangerous virus transfers easily through email and file/application downloading.
- If you are unable to buy the commercial version due to financial constraint
Best free computer virus removers
AVG free edition
AVG free edition is among the top free computer virus cleaner downloaded by most people.
Strength
- Freely available for home use only
- Good level of protection
- Virus definition can be updated daily
- Capable of protecting a virus comes through email, also inspects a website you visit
- 64-bit version is available
- Behavioral blocking capability
Weakness
- Low scan speed
- No program update
Avira Anti-virus personal edition
Avira is the other best free anti-virus program worth to install.
Strength
- Freely available for single computer
- Performs well in protecting against viruses, spyware and rootkits
- Minimal usage of systems resource
- Capable of protecting a virus comes through email, also inspects a website you visit
Weakness
- No protection for email and website visit attack
- Has problem updating its definitions
Avast Anti-Virus free edition
Avast is also the popular free computer virus cleaner which is effective for personal computer usage.
Strength
- Good level of protection
- Built in with email, webpage, and network protection capability
- Boot scanning
- Minimal usage of systems resource
Weakness
- Low scan speed
- No program update
Microsoft security essentials
Strength
- Good level of protection
- Ideal for removing existing malwares
- Minimal usage of systems resource
- Fast updates
Weakness
- Low scan speed
- Requires genuine installed Windows operating system on your computer
ClamWin and Panda cloud anti-virus programs are the other freely available AV’s for personal use.
Generally, free computer virus cleaner is capable of protecting your computer though it has some limitations comparing to paid version.
What is computer software?
What is computer software? Every day in one way or another, we use computer to perform our tasks both at the office and home. It is possible to say that today’s world is computer driven world, where every task is done through computer. And without the usage of software, computer does nothing.
Computer software controls how a computer should execute a particular type of task.
Generally, computer systems are categorized into two major parts: Hardware and Software.
In this article we will try to see the basics of computer software and its type.
But first, what is computer software?
Definition of computer software
To put it simply, computer software is a set of instructions that tells a computer what to do. Computer software controls and governs the process of a computer. Without computer software, the hardware part is useless. There is no way to communicate with the computer unless you installed system software on it.
Software is written and developed by computer programmers using programming languages. When we talk about computer software, it includes the two main groups of software.
These are called System Software and Application Software. The other but an optional type of computer software is Programming language.
System Software
Commonly referred as Operating system, System software plays a key role in computer systems. It is responsible for managing and controlling the activities and functions of computer hardware and application software. We can say that operating system serves as an interface between computer hardware and application programs and a user.
To run any type of application program, you must install the right Operating system. What is computer software – continued…
The major functions computer system software
- Manages computer processing activities
- Managing files
- Handle computer memory
- Serves as an interface between computer user and hardware
- Providing access to system resources
- Facilitate the overall activities of each programs installed on it
- Providing an interface for peripheral devices and network access
- Allows user to run application programs
In addition to Operating system program, hardware drivers and other system utility programs which assist and maintain the proper function of a computer are also grouped into system software.
Device/hardware drivers control the individual components of computer such as printer, network card, and sound card.
Utility programs help you to maintain computer performance and security. Anti-virus program and registry cleaner are example of system utility programs. What is computer software – continued…
Example of Operating System Software
MS-DOS (Microsoft Disk Operating System) is the first operating system introduced by Microsoft, the dominant software producer in the world, in the 1980s. Since then several versions of system programs are developed by Microsoft and other IT companies.
MS-DOS has command line interface unlike the modern operating systems which use Graphical User Interface (GUI). GUI allows a user to interact with a computer/software using graphics and icons.
Operating systems can be categorized further into two categories:
Personal computer OS and
Enterprise/Workgroup OS.
Some of the popular Personal computer OSs include:-
- Microsoft products
(research shows 80% of computers in the world installed with Microsoft OSs)
Windows 95, Windows ME, Windows 2000, Windows XP, Windows Vista, Windows 7 and Windows Mobile
- Apple Computer System programs
Mac OS and Mac OS X
- Linux
It is developed by Linus Torvalds, a student in Finland, in 1991. Linux is an Open-source operating system, means the source code is available freely.
- UNIX
- Solaris
- Red Hat Linux
Enterprise/workgroup operating systems are powerful and sophisticated comparing to Personal computer OS. These types of system programs are developed for computers such as Servers and Mainframes.
Mainframe computers are used in large organizations, governmental offices, military and other business companies where a lot of resource is shared through a network. What is computer software – continued…
The following are the popular enterprise and workgroup operating systems:-
- Windows Advanced Server
- Windows Server 2000, 2003 and 2008
- UNIX - Red Hat Linux
- MPE/iX are servers software
– designed for HP Computers
Application Software
Application Software is a type of program which assists a user to execute a specific task on a computer. It helps a user to solve particular problems. Application programs use system resources and hardware through System programs.
In each field of work and industry, several kinds of application software are developed and still new programs are developing.
For example, Peachtree Accounting is a computer application program specifically developed for accountants to manage of financial activity in a given organization. AutoCAD is for Mechanical and Civil Engineers; where as Adobe Photoshop is for graphics designers and photographers.
Some of the tasks of Application programs
- Word processors, Spreadsheet, presentation (Microsoft Office Suite)
- Database manipulation
- Accounting and Financial recording programs
- Graphics (Adobe Suite) programs
- Engineering Applications (AutoCAD, ArchiCAD, InRoads, StaadPro, SAP, Eagle point etc..) for designing roads, building and bridges
- Desktop publishing (Adobe Indesign, Pagemaker)
- Games
Conclusion
In summary, computer software plays a great role in computer systems. Without it computer hardware does nothing. In this article we have discussed about computer software to answer the question, “what is computer software?”
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Computer network technology
In today’s fast and competitive world, the usage of computer network technology is one of the requirements for the success of a business or career. This technology enables computers to get connected each other so that they can share different types of resources that are available within the network. Generally, as far as there are two or more computers, the networking concept can be implemented.
In this article we will try to answer the following questions and discuss about computer network.
What is the role of computer network technology? In what way computer networking is essential? What are the main types of computer network and the tools needed to install? Where and when should we implement computer network in our business and occupation?
What are the benefits of computer network technology?
Computer networking enables you to share both hardware devices and software. Actually, the main purpose of computer network is SHARING. You can share wide varieties devices and resources.
The following are some of the most common devices that can be shared over a network.
- Printers
- Fax machines
- Storage devices and CD/DVD drives
- Computer Local drives
- Scanners
- Modems
- Applications
Why should we share resources via a computer network? There are two main reasons: cost and time.
Using a computer network benefits both large and small businesses by reducing costs made on expensive hardware. These devices include printers, scanners, fax machine and copiers. For example, rather than buying printers for each office, it is more profitable and wise decision to connect several computers and share a single centralized printer or resource.
Other than reducing hardware costs, computer network technology is used to share a single Internet connection over multiple computers, helps to control your data and information, enables to work on a single document, exchange mails, helps to work a task using networked applications, easily access data without going to the source computer, troubleshoot computer problems easily, installing programs to multiple computers over a network and many more.
In addition to trimming down hardware costs, you can also save much time after the implementation of computer network technology in your business. Depending on the type of work you have, computer network can be implemented both at the office and home.
Computer network technology
Types of computer networks
A Network can be classified based on the physical distance between two points. Some of the major computer networks are the following:-
Personal Area Networks (PAN)
It is a type of wireless network than can connect devices at a limited distance (30ft). Using PAN you can download data from digital camera to a computer (laptop) or print to a printer without connecting each other with a cable. Bluetooth connection is grouped into PAN communication type.
Local Area Networks (LAN)
Local Area Network is the popular computer network technology type which connects computer systems within a small area. These small areas include a single office, a building with several floors or home. LAN network is the best network type that can be built in these areas.
There are two types of LANs: peer-to-peer networks and client/server networks.
In peer-to-peer network:-
- Each computer is connected independently
- It is to share files and hardware devices such as printers
- There is no dedicated server
- The cost is minimized, it is cheap and easily installed
- The performance may decrease
- Ideal for small business or home network
- Low security comparing to client/server networks
In client/server network:-
- There is a dedicated server. Server is a type of computer built in with high end processors, more memory space and larger storage capacity. Servers operate with a special type of operating systems such as Windows server 2003, 2008, Linux and Unix.
Depending on the capacity, servers can accommodate several users at the same time. Servers can be used for several purposes: files server, e-mail server, and print server. In my office we use one server for file, print and e-mail purposes.
- Each workstation or client computer connects to a server not with the other client computer. A client computer is any type of computer that is connected to a server.
- Only authorized users can access in client/server network
- It is secured centrally
- All the sharing of resources in the network is controlled by the server
- It is very expensive to install
Metropolitan Area Networks (MAN)
Metropolitan network is the other type of computer network that covers a campus or city. Governmental offices, universities and colleges have utilized this type of network.
Wide Area Networks (WAN)
A wide area network is a network that connects large geographic area. WAN is a group of Local area networks. Local area networks found in different regions can be connected through fiber optics, satellite or leased phone lines. Internet is the largest network in the world. It is a collection of several interconnected networks that shares information freely.
Computer network technology tools
Computers can’t connect each other unless proper tools and protocols are met. If you want to have a network at your office or home, you should know the tools needed for it. First, determining the type and network architecture will dictate the type of hardware you are going to use. This will save you from unnecessary expense.
The following are the minimum tools you need for typical computer network
- Cables that include Coaxial, UTP (unshielded twisted pair) and fiber optics. You can also connect computers using wireless connection.
- Network card (most recent system has built in 100Mbs/1000Gbs network adapters)
- Communication rules or Network protocols – TCP/IP (transmission control protocol/internet protocol) the most popular and the standard protocol that supports both internet and LAN networks.
- Network operating system
- Hardware devices that are going to be shared (printer, fax, scanner)
There are other advanced equipments that can be included in a given network. However, it all depends on the type of network you have. Server, Switches, Hubs are a must for large networks.
Conclusion
This is just an overview of computer network technology. As we have already seen in the above article, the role of computer network is significant in any business whether it is small or large. In any case, implementing this technology both at the office and home level is essential for business and individual career success.
Computer network components
Computer network components include the major parts that are needed to install a network both at the office and home level. Before delving into the installation process, you should be familiar with each part so that you could choose and buy the right component that fits with your network system.
These hardware components include cable, Hub, Switch, NIC (network interface card), modem and router. Depending on the type of network you are going to install, some of the parts can be eliminated. For example, in a wireless network you don’t need cables, hubs so on.
In this article we will discuss about the main computer network components required to install simple computer network, often called LAN (local area network).
Computer network is a group of two or more computers that connect with each other to share a resource. Sharing of devices and resources is the purpose of computer network. You can share printers, fax machines, scanners, network connection, local drives, copiers and other resources.
In computer network technology, there are several types of networks that range from simple to complex level. However, in any case in order to connect computers with each other or to the existing network or planning to install from scratch, the required devices and rules (protocols) are mostly the same.
Ok, let us go and see each component in detail…
Major computer network components
Computer network requires the following devices (some of them are optional):-
• Network Interface Card (NIC)
• Hub
• Switches
• Cables and connectors
• Router
• Modem
1. Network Interface Card
Network adapter is a device that enables a computer to talk with other computer/network. Using unique hardware addresses (MAC address) encoded on the card chip, the data-link protocol employs these addresses to discover other systems on the network so that it can transfer data to the right destination.
There are two types of network cards: wired and wireless. The wired NIC uses cables and connectors as a medium to transfer data, whereas in the wireless card, the connection is made using antenna that employs radio wave technology. All modern laptop computers incorporated wireless NIC in addition to the wired adapter.
Network Card Speed
Network Interface card, one of the main computer network components, comes with different speeds, 10Mbps, 100Mbps, and 1000Mbps, so on. Recent standard network cards built with Gigabit (1000Mbps) connection speed. It also supports to connect slower speeds such as 10Mbps and 100Mbps. However, the speed of the card depends on your LAN speed.
For example, if you have a switch that supports up to 100Mbps, your NIC will also transfer a data with this same speed even though your computer NIC has still the capability to transfer data at 1000Mbps (1Gbps). In modern computers, network adapter is integrated with a computer motherboard. However if you want advanced and fast Ethernet card, you may buy and install on your computer using the PCI slot found on the motherboard (desktop) and ExpressCard slots on laptop .
2. Hub
Hub is a device that splits a network connection into multiple computers. It is like a distribution center. When a computer request information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.
Currently Hubs are becoming obsolete and replaced by more advanced communication devices such as Switchs and Routers.
3. Switch
Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It uses physical device addresses in each incoming messages so that it can deliver the message to the right destination or port.
Like Hub, switch don’t broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.
4. Cables and connectors
Cable is one way of transmission media which can transmit communication signals. The wired network typology uses special type of cable to connect computers on a network.
There are a number of solid transmission Media types, which are listed below. - Twisted pair wire
It is classified as Category 1, 2, 3, 4, 5, 5E, 6 and 7. Category 5E, 6 and 7 are high-speed cables that can transmit 1Gbps or more. -
Coaxial cable
Coaxial cable more resembles like TV installation cable. It is more expensive than twisted-pair cable but provide high data transmission speed.
Fiber-optic cable
It is a high-speed cable which transmits data using light beams through a glass bound fibers. Fiber-optic cable is high data transmission cable comparing to the other cable types. But the cost of fiber optics is very expensive which can only be purchased and installed on governmental level.
5. Router
When we talk about computer network components, the other device that used to connect a LAN with an internet connection is called Router. When you have two distinct networks (LANs) or want to share a single internet connection to multiple computers, we use a Router.
In most cases, recent routers also include a switch which in other words can be used as a switch. You don’t need to buy both switch and router, particularly if you are installing small business and home networks.
There are two types of Router: wired and wireless. The choice depends on your physical office/home setting, speed and cost.
6. Modems
A modem enables you to connect your computer to the available internet connection over the existing telephone line. Like NIC, Modem is not integrated with a computer motherboard. It comes as separate part which can be installed on the PCI slots found on motherboard.
A modem is not necessary for LAN, but required for internet connection such as dial-up and DSL.
There are some types of modems, which differs in speed and transmission rate. Standard PC modem or Dial-up modems (56Kb data transmission speed), Cellular modem (used in a laptop that enables to connect while on the go), cable modem (500 times faster than standard modem) and DSL Modems are the most popular.
Conclusion
Whether you want to install a network at your office or home, these are the required computer network components you need. Though, depends on your situation some of the devices can be disregarded. For home network using a Router is suitable since it also bundles a switch.
Hope this article gives you some insights about PC network components.
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