Viruses are small programs designed to hide inside of other programs.
Viruses often accomplish some degree of mischief.
Many viruses claim to have no harmful effects, but any program that enters your system under false pretenses is at least a trespasser, if nothing worse. How Viruses Spread You can catch a virus whenever you accept any files or disks from anybody. Safe Computing Short of never sharing files, the best next step is to limit the number of places from which you receive files. The Wazzu virus mentioned above is a macro virus. To protect yourself you really need a virus protection program.