Considering they released a 72 page upgrade instruction guide with the SP2 I would have thought reading that would have been a good idea, especially with all the comments going around about problems with the SP2 after installing it. Have a look at http://www.winxpnews.com you might find helpful and useful info there that will resolve the issue.

I never install service packs within the first 2 months of official releases for this exact problem. Why, because the bugs are out of the SP by then usually.