What FREE anti-virus software do you guys use and trust?

Well, if your computer already infected (I mean really infected! severely! :p) then stop installing any new antivirus before you remove the virus. Many modern virus now inject themselves into the system and will mess up with your antivirus system, even it is a new installation. One example, I have scanned one computer, it doesn't have antivirus at first, then I install free avira version 8 (early 2009), and scan it. It can detect the virus and have the option to "Repair" it. Next step I try to copy the infected virus into a clean computer with latest avira update (same version, same update definition). It also detect but it doesn't give "repair" option for this virus. You see what I mean here? Installing new antivirus to an infected computer doesn't really help for me. The best thing to do is to scan the disks via another computer or simply reinstall everything. For free antivirus, I would suggest avira as I have use it for 3 years and my PC in home have no trouble at all with viruses.

I'm always using the anti-virus software which I was paid for. I don't believe that there will be good performance of FREE anti-virtus software. So I prefer to chargeable software rather than FREE one. Actually it's not expensive.

hi there, try avast free anti-virus it is quite good, and similar is avg, both are good but i like avast more...

I also use avast like the first respondent, but it is not free haha, it is pirated hehe. It is licensed. I used to use the free version of avg, but it isn't any good, maybe the licensed one is way better.