What's the best free antivirus for windows?

I've always been a format and reinstall kind of guy, but now I have a lot of programs and files I don't want to lose by formatting. So I'm looking for a free antivirus

I've browsed through a few questions and the popular vote seems to be for AVG.

What's the best free antivirus for windows?network security

AVG is the best and is often recommended by tech professionals. They also have a good free antispyware program, which is worth installing.

What's the best free antivirus for windows?norton internet security

i go with AVG too, i disabled the free virus programs provided with my Internet service just to use it.

AVG is updated daily and always the most thorough program I have ever used.
I use AVG
yap im using avg the free edition and it really works it detects viruses fast when it is upgraded it is really helpful. try seraching on the net..
Steve, keep in mind that FREE and BEST don't go together.!

Spend about $60 to $70 bucks and get Norton 360 or something else in that category.
AVG because Norton anti virus runs out and then a new virus appears again over and over and AVG is way higher than Norton Antivirus
Using avast here on three machines.

You might want to look into an imaging solution for backup - Acronis True Image is the preferred imaging software.