Free Anti-Virus Program for 7 Year Old Computer?

[Secret Agent Man]

My parents' computer is running Windows XP on a 2001 eMachines computer with low specs (less than a GHz processor, the RAM's no more than 512 MB (I think it's actually 256), etc.) Anyone have any recommendations for a good, free anti-virus program that isn't nagware? For the past few years they've had AVG Free, but version 8.0 sucks, and now the current version keeps nagging them to update (claiming that it's "mandatory"), so it's time to switch.

[Katsurugi]

The only other free antivirus program that I could recommend is avast!. I believe it's free and I haven't really had too much experience. But it's the one I'm thinking about replacing AVG 8.0 with on my sister's computer. I've heard only good things about it though.

[atmuh]

version 8.0 sucks

no it doesnt

[VCR Channel]

I had avast! before. It was alright, but I switched to AVG 8.0, and I like it a lot more.