Final update!! (I hope)
I think we finally have the lockup problems fixed...I was trying to play a DVD a couple days ago and PowerDVD wouldn't play because of what it called "video card settings and copyprotection". When I played it in my updated Windows Media Player my computer programs all locked up just like the problems I was having before updating to sp2. I got to thinking it seemed like my video card was having a problem displaying the DVD so I should see about updating the drivers. I have an Nvidia Geforce 3 and in the past it was a little iffy to keep changing drivers if the one you had was working fine. Lately they've updated so that all the Nvidia cards can use the same driver with winxp and it seems to be very much necessary if you have installed the sp2. I now have the newest driver and I have been trying my best to use as much resources as possible...running DVD's, video capturing and editing, making rar files, running music programs etc. Nothing has locked up since.
My apologies for thinking Avast was somehow contributing to the lockups

. I think it was a coincidence and perhaps turning off the Avast was saving just enough of the memory (albeit a small amount) to keep me surfing for a long enough time that I thought the problem was fixed by turning it off. I am a happy camper right now with Avast dutifully running 5/6 providers and keeping me protected!!

Thanks for all the help folks!