Anti-virus programs can detect known computer viruses and protect your system against some new, unknown viruses. These programs check your system for viruses each time your system is turned on, and can also be configured to run periodic full system checks. Anti-virus programs also check any files you download from the Internet, or copy from a floppy disk or CD.
If your system is infected with a computer virus, you can use an anti-virus program to detect the virus and remove it from your system.
You should configure your anti-virus program to run weekly or daily scans of your system. You should also configure the program to automatically scan all files that you download to your PC.