I agree with MB ,, you have the ROLL BACK option of which you can find FULL instructions in your help option,, start> (right column) help...do a search in help on ROLL BACK and you will get the instructions,,,
I have heard of PC games causing some havoc on XP,, anywhere from your issue, not shutting down, to lost NIC,, corrupt office programmes , etc,,
not sure what is overwriting what ?? cant find anything that pin points why the issues are coming up,,
Uninstall the game, do the roll back,, reboot,, then disable Antivirus, and have NOTHING else open,, reinstall the game via ADD/REMOVE progs,, to do this you will have to cancel the install at the autorun and then go into the control panel to the add/remove applet, browse back to the cd and look for the setup.exe
in addition,, go to windows update and get ALL the recent patches and fixes,,
remember to Defrag regularily,, this is important in XP!!
best of luck , dont give in!
cheers,