Important Tips

Just One, Not Two -- Never use two anti-virus products at the same time. Completely uninstall one before installing another. Use the vendor's uninstall utility or if not available, use the Windows XP add/remove software tool in the control panel.

Patches & Updates -- Anti-virus software is only as effective as its most recent update because it is inherently reactive treating "known" threats. So when you install anti-virus software, go to the vendor's web site and update the program and virus definitions immediately and then turn on the auto update feature (if it has one). If you want to be ready for the next big bad thing before your anti-virus signatures can be updated, consider Zero-Day Protection.
 
Get Online Protection Too -- Consider using an Internet service provider or email service that includes server side anti-virus and spam email filtering as a second layer of defense. If possible, use different anti-virus software on your home computer than your ISP or service uses on their servers.

Spyware & Trojan Horses -- Some anti-virus products work on spyware, Trojans and other malware. If yours does not or has limited effectiveness (read reviews and test results), get a separate product, see our Anti-Spyware and Anti-Trojan pages.