I am pretty sure I had this game working underXP with no compatability modes enabled, I got it for £7 so I thought I would give it a whirl, that was sometime this year so it was definatly under XP.. I do remember it having a problem but the patch sorted it out (Nvidia related problem)
I can suggest the usual stuff like compatibiility mode, latest drivers etc, but older and unsupported games like this, will often not work under WindowsXP.