As far as I know, most "cpu cooling" programs are useless on XP. This is because they work by telling the OS to not use the processor when it's idle and XP has that ability built in. I did use some cpu slowdown utilities (mainly to run older turn-based games on my computer) but don't have them now, look for them here, http://www.majorgeeks.com/downloads14.html
MG have a really great collection there.
PS: Are you trying to overclock?