Well i only included the .inf file for completeness if it's no find by searching your PC then you dont need to remove it. (As you dont have it anyway)
The only other thing's i can think of is to re-calibarate the joypad within Start - Control Panel - Game controllers
Take your time re-calibrating it make sure to get it exactly right and try NFSU again.
The other thing you could do is leave the joypad plugged in but go to Hardware manager and un-install the pad from there and restart the PC.
Good luck
Last resort re-install windows clean and plug the joypad in and let windows auto detect it, i.e. no drivers.