Part of the key in fighting computer viruses is to identify the possible paths of virus infection. Clearly a strong, and enforced, company policy against any illegal software is the simplest step in preventing virus infection. Virus are either brought in by contact with virus infected disks, or rarely by local programming. A computer virus is a program that can infect other programs by modifying them to include a copy of itself. When the infected programs are executed, the virus spreads itself to still other programs.
Viruses can spread rapidly in a network or computing system and can cause widespread damage.
Unlike many other security threats, viruses can enter a given computing system without anyone intending them to. Use good general security practices. Keep good backups of critical data and programs. Develop a plan to deal with viruses before there is a problem. Isolate users and system.