[CORed]

If I understand correctly, the wheel is physically frozen (won't move at all). If that's the case, obviously reinstalling the driver won't help. If you've taken it apart, cleaned it, and can't see any obvious, fixable mechanical problem causing the wheel to stick, I'd say it's time for a new mouse. I've never taken a mouse apart farther than popping out the ball to clean off the rollers, so I don't have enough idea of how the scroll wheel works to give you any idea of what to look for.

If, OTOH, the wheel moves bet doesn't do anything, it could be a software (driver) problem, but might be a hardware thing, i.e, an elctrical failure, which means you probably need a new mouse.