If a PS/2 mouse,
1. reinstall the mouse driver.. try the intellimouse microsoft driver... if it doesn't help
2. you will probably need to replace the PS/2 mouse with a USB mouse
You could alternately use a USB - PS/2 adapter to use the USB generic driver, but if the mouse is damaged it may not even work with a USB adapter, all depends on the mouse age and condition. If it's a USB mouse, try it on different USB ports and/or cleaning the LED or Laser emiter.