Best free antivirus?

Ive had norton ever since I bought my computer but when they came out with the new version, they decided not to support the old, and to top it off they went up on the subscription service.
I'm looking for something that offers free updates and script blocking.
BTW I'm running windows xp.

any suggestions?

XP box needs a reformat and reinstall every six months

What the hell are you doing?

Let's see: on my old computer I never reinstalled 98. It ran fine for four years. On my current computer I've never reinstalled XP. It's run just fine for two years.