That's what I am going to do, I have used AVG on my XP systems for a couple years now and it has worked well. Avast was one of the first programs to work properly with Vista during the beta period, and I had no problems so I stuck with it. I have mostly migrated to Vista, and was using it as my primary boot OS but messing up my morning newspaper and coffee was a major holdback . XP is going to be a multi-boot option on my system for some time regardless (along with SUSE or another Linux OS), but on a fast desktop Vista is quite pleasant to use, especially now with one less minor but quite irritating problem.