My middle mouse button failed.  It was only accepting clicks at a high force level, and now is not registering at all.  I was attempting to clean the mouse and removed all 5 screws from the bottom.  Unfortunately, I cannot figure out what the next step is for taking the mouse apart to try to clean the middle-click sensor.  I'd rather get some instructions rather than end up braking something, but unfortunately I can't find instructions in the FAQ or through searching the boards.