Try going to run,type:Msconfig services tab,click on the box,"hide all microsof
services",then disable all,this disables all third party services at start-up,apply,ok
restart computer.If the computer speeds up significantly on start-up,you'll know it
not in xp,evaluate from thier.Msconfig will reopen back in desktop,re-enable service
you disabled before.This wont fix anything,it just gives you an idea on where to look.