Virus

In the context of computer software, a virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium such as a floppy disk, CD, or USB drive.

Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer Worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk or cause the operating systems not to function properly. Not every virus causes damage to computer but some viruses simple flash annoying messages. Viruses are written to attack specific kinds of operating systems, that is a virus infect computer running with Microsoft windows operating systems will be harmless to computer using Linux operating systems. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.

There are many viruses operating in the general Internet today, and new ones are created and discovered every day.

The best way to protect your computer again viruses is to use Anti-Virus software. Anti-Virus software is developed to remove a virus from your system. Most of the Anti-Virus applications available today have a real time monitoring that constantly scans your system in the background for any virus activity. They make use of virus definition files for known viruses and heuristic technology to detect unknown viruses. Every day there are new virus emerge in the Internet, It is important thing that you must keep your anti-virus software updated to ensure you are protected against the newest threats.

Signs of viruses

• Your computer runs more slowly than normal
• Your computer stops responding or locks up often
• Your computer crashes and restarts every few minutes
• Your computer restarts on its own and then fails to run normally
• Applications on your computer don't work correctly
• Disks or disk drives are inaccessible
• You can't print correctly
• You see unusual error messages
• You see distorted menus and dialog boxes

Avoid computer viruses

• Use an Internet firewall like zone alarm from ZoneLab. (Note: Windows XP with SP2 has a firewall ready built-in and turned on by default).
• Computer which run on Microsoft XP OS, turn on Automatic Updates.
• Buy industry standard anti-virus software, such as AVG anti-virus software and keep it current.
• Never open an e-mail attachment from someone you don't know.
• Do not opening an e-mail attachment from someone you know, unless you know exactly what the attachment is. The sender may be unaware that it contains a virus.