Mighty Mouse: can scroll and click, but cannot move (cursor does not move)

Ive been using my mightymouse for a couple months now, but couple days ago it stopped moving when i booted up my mac. I tried removing the device from the bluetooth panel and then connecting again, changing my batteries, changing the surface, but nothing works. the bluetooth still connects fine to my macbook pro, but the mouse cursor wont move when i use my mighty mouse! please help me...