Known by its red umbrella icon, Avira
provides excellent protection against viruses while requiring the least
amount of system resources. For this reason, Avira is the best choice
for users concerned about PC performance. Unfortunately, Avira displays occasional
ads, encouraging its free users to upgrade to a paid version; however,
Avira's extremely high detection rate makes this free anti-virus
software our No. 1 choice.
MSSE provides
real-time, active protection against a myriad of malware threats. This software also includes ongoing protection and updates at no cost.
Currently available for XP, Vista, and 7, this free product from
Microsoft may well change the pricing landscape of commercial anti-virus
products.
AVG is a popular
choice among free anti-virus programs. This anti-virus program includes
regular, free anti-virus definition updates. Keep in mind that AVG,
along with Avira and Avast, is only free for home and personal use.