- Created on 27 March 2006
A virus is a program written to cause mischief, damage or gain entry to a computer system. A mild virus might only be a slight nuisance, or even amusing. However, most viruses do damage, whether to your files, your registry, or even your hardware. Your computer can pick up a virus when you copy a seemingly normal file from a diskette or download it from the Internet. Viruses are hard to detect, easy to propagate, and difficult to remove.