i want my game prince of persia 4 speed in windows xp because it's slow
Probably nothing to do with Windows but your computer speed.
Check here, http://en.wikipedia.org/wiki/Prince_of_Persia:_The_Forg...
If your system is slower than the recommended system listed, you can try lower resolution in the game and lower graphic settings. If your system is barely on the minimum specs, you need to upgrade it.