computer

A computer virus is a computer program that can copy itself without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. 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.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 form of malware that presents itself as a legitimate program. In contrast to viruses, Trojan horses do not insert their code into other computer files.
Spamming is the abuse of electronic messaging systems to send unsolicited bulk messages, which are almost universally undesired.
Antivirus software consists of computer programs that attempt to identify, thwart and eliminate computer viruses and other malicious software (malware) but not for spam mail.