Puzzling indeed. No quick and easy answer comes to mind, but a few questions arise:
Is the mouse wired or wireless?
If wired, is it USB or mini-din ?
Is XP current with the latest updates?
Are the correct /latest drivers for the current mouse installed?
Are the drivers for previous mouse creatures removed? (Check control panel / Add or remove etc ... Caution! proceed carefully here)
As I said, no easy or immediate solution, but a clue may lie in answers to the above.
Good luck,
FOR