Well, there's Mo'Slo, which is a clock-slower for emulating DOS games...comes in invaluably for we gamers who love those "ancient games."
I don't know if it would run on XP, but let me see if I can find a link for it. Here you go:
http://www.hpaa.com/moslo/
Check it out and see if it will run on your system.
Cheers,
-Sazerac