computer virus

A computer virus is a program or piece ofcodethat is loaded onto your computer without your knowledge and runs against your wishes. Viruses can also replicate themselves. Allcomputerviruses are man-made. A simple virus that can make acopyof itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all availablememoryand bring thesystemto a halt. An even more dangerous type of virus is one capable of transmitting itself acrossnetworksand bypassingsecuritysystems.Since 1987, when a virus infectedARPANET, a large network used by the Defense Department and many universities, manyantivirus programshave become available. Theseprogramsperiodically check yourcomputer systemfor the best-known types of viruses.Some people distinguish between general viruses andworms.A worm is a special type of virus that can replicate itself and use memory, but cannot attach itself to other programs.