Definition: A virus is a software program, script, or macro that has been designed to infect, destroy, modify, or cause other problems with a computer or software program. Users can protect themselves by installing an anti-virus protection program.
Find information about the latest virus threats and updates at Symantec Security Response
Also see: anti-virus, Boot sector virus, CMOS virus, Companion virus, Executable virus, Hoax, Intruder, Logic bomb, Macro virus, MBR virus, Multipart virus, Non resident virus, Overwrite virus, Polymorphic virus, Resident virus, Stealth virus, Trojan horse, Vaccine, Security definitions, Worm, Zoo
Method: Once within the computer or network, it causes that computer or network harm by deleting, modifying, distributing, or otherwise manipulating the data.