Perhaps downgrading drivers would help solve the problem instead of upgrading. But it is a "dangerous path" to take, because it can mess up so many other things.
But getting the game to run on WinXP is a gamble, it wasn't made for neither the hardware nor the software, so many strange things can happen. But you sound to have tried all the things I would have suggested...
Do you run an Antivirus program? then if possible, try to deactivate/uninstall it and see if that makes a different. Sometimes the protect features of these programs will mess with your games/software.