Use Antivirus

Antivirus software is like soap, it is good (not perfect) protection against getting infections.

Infections from viruses, trojans & worms make computers unreliable. They can cause crashes, data loss, and can even bring a network down or trash your computer beyond repair. Antivirus software works to stop viruses before they have a chance to do their damage.

Install antivirus software and keep the signatures up-to-date. Nearly all antivirus software does this automatically. However, you should periodically check to see that the updates are successful. Updates can fail if your subscription has expired or if you're blocked by a firewall.

Also, periodically scan of your entire hard-drive. This may clean up viruses that got on your computer before a signature was available.