Best free antivirus for Windows?

If you're running windows ME or less, is still regularly updated.

I like http://www.free-av.com/.

I used to use avg, but I got fed up with it's need to download the entire database every time it updated (apparently). I'm now using avast! and would recommend it, although if anyone knows how to switch off the Klaxon I'd love to hear from you. ;)

AVG is very good.

I use http://www.avast.com, which seems to work well (though it hasn't come in contact with an actual virus yet on my system, so it's tough to tell). It's pretty feature-rich, but, like twine42, I'd love to be able to make it 'quieter'; for me, the pop-up in the corner every time it updates the virus definitions gets old fast.

In addition to AVG or other anti-virus software, I would use http://www.safer-networking.org/ to catch spyware and other crap that is missed. It's a great product and free to boot.

Another AVG user (no virus yet). Also, from time to time use McAfee http://us.mcafee.com/root/mfs/default.asp?cid=9059.

Ditto for AVG. I managed to contract something which spread throughout my home network. AVG cleaned everything up and has kept me safe since then.

I've used AVG for a few months, but recently (about 2 weeks ago), the update feature stopped working: it does the whole song and dance of downloading, but it doesn't actually update the virus defintions for some reason. Hence my question.