Scroll-wheel thingy on mouse is broken....

[dcasper70]

So I have a standard Microsoft Wheel Mouse, and the scroll wheel suddenly stopped moving. I've taken it apart and it looks fine. I even took the wheel out of it's housing and cleaned out the whole thing.
When out of the housing, the wheel spins freely in the receptor (the thing that converts the spin to electrical signals). When I put it back into the housing it is just frozen.

Any thoughts? I'll just buy a new one unless someone's got a quick and simple answer for me.

Thanks