What is a Virus?
A virus is a program that infects systems by rewriting files, or by inserting or attaching a copy of itself to a file (including email files). When an infected file is opened, the embedded virus is executed. Often, users don’t realize that this is happening in the background. It may replicate itself within one computer, but to infect other machines, it must be passed on in a program, email file or attachment, infected diskette or other “removable media,” although it can’t spread itself from computer to computer without help.
[return to top] Virus: A program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. Most viruses can also replicate themselves. All computer viruses are manmade. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems. Since 1987, when a virus infected ARPANET, a large network used by the Defense Department and many universities, many antivirus programs have become available. These programs periodically check your computer system for the best-known types of viruses. Some people distinguish between general viruses and worms. A worm is a special type of virus that can replicate itself and use memory, but cannot attach itself to other programs.
What are Viruses, Worms and Trojan Horses, as defined by Microsoft: A virus is a piece of computer code that attaches itself to a program or file so it can spread from computer to computer, infecting as it travels. Viruses can damage your software, your hardware, and your files. Virus (n.) Code written with the express intention of replicating itself. A virus attempts to spread from computer to computer by attaching itself to a host program. It may damage hardware, software, or information. Just as human viruses range in severity from Ebola to the 24-hour Flu, computer viruses range from the mildly annoying to the downright destructive.
A virus is an unwanted file or set of instructions that attaches itself to files in your computer system, usually causing harm to your computer. It replicates itself as the file is shared from computer to computer. Viruses are not naturally occurring bugs. People, who want to damage your computer system, create them. You can protect yourself from viruses by always checking programs and files that you download from the Internet with a virus protection program. You can purchase protection programs from a computer store.
