Whats a good FREE antivirus software?

Try Spybot Search and Destroy. You have to download both the progeam and the detection updates. It's free but they accept donations.

http://www.safer-networking.org/en/download/index.html

My uncle downloads AVG for free and has never had any problems with it so I would recommend it highly.

At home, we use AVG for the pcs and iAntiVirus for Macs. Both work great and are fully functional.
http://free.avg.com/us-en/download
http://www.iantivirus.com/download/

At work, Recently we use free antivirus that comes with Zenok online backup, well for us it's been very functional.
http://free.zenok.com/

Hi,
I am regular user of axcss site for downloading for free software.You will found many antivirus and other software free for download.
http://www.axcss.com/