A computer virus is a self- replicating computer program written to alter the way a computer operates, without the permission or knowledge of the user. While viruses can be intentionally destructive by destroying data, some viruses can be benign or just really annoying. Viruses can increase their chances of spreading to other computers by infecting files on a system. A virus can also spread from one computer to another when its host is taken to the target computer by using a disk, USB, or a network over the Internet.
