There are many good and free computer virus protection programs. AVG, ClamWare, PC Tools, Avast, Panda, Comodo, Avira, and F-Prot are some of the favorite free computer anti-virus protection programs. From all of these AVG still appears to be the leader from all of the downloads and great reviews that it receives. Many of the popular and
expensive commercial products have the tendency to slow down your computer because of all the unnecessary scanning they perform in the background. I faithfully purchased the latest commercial products year after year until I could no longer deal with the lost performance issues they imposed on my computer. I have enjoyed using AVG over the last few years because of the simplicity and speed of the product. It will update daily any new virus signatures and provide excellent protection. I really only use an anti-virus program to alert me of an infection. Once infected my system could be compromised with a number of other undetectable programs, such as down-loaders and key-loggers, that will cause reinfections and possible loss of passwords and other valuable personal information, even if you are able to clean the viruses off your computer. I use an imaging program that will quickly restore my computer to a known good configuration in a few minutes with the latest free computer virus protection installed.
Norton Ghost and Partimage are my two favorite computer imaging programs. I prefer Norton Ghost because I can run it from a boot DOS partition and it runs very quickly. I also use Norton Ghost to daily restore 35 lab computers that I maintain in a high school lab where the users have complete administrator rights that they abuse daily. They need full access and admin rights to complete their Computer Repair labs.
You might also visit Free Computer Protection website where you will find additional information that you might find useful.