Might I suggest a web site that will definately help you speed up your Windows XP and is probably quite a bit less confusing to understand. The guy that made this site knows everything there is to know on the topic. Must be close to 800 pages with tweaks and other things you can do to speed up your Windows XP. As long as you read his suggestions carefully they should drastically speed up your system. I'll give you guys the link:
http://www.blackviper.com/
Anyway, I may be reiterating something many of you already know, but if not then I think this suggestion will be more then helpful in speeding up XP.