A computer virus can be defined as a software program that attaches itself to another program in computer memory or on a disk, and spreads from one program or disk or computer to another.
Viruses can damage data, cause the computer to crash, display messages or lie dormant.
Before you use any disk, it is advisable to scan it for viruses. Don't ever assume a disk is clean unless you know it is clean. It is wise to assume that anything you get off the net might be infected. Therefore, running a scan on everything you download is a very good idea. You can pick up a copy of anti-virus software at the HelpDesk.