As bassfisher6522 mentions, a little more info about you system might help. What type/brand of mouse is it and how is it connected?
Does it happen all the time, or can you tie it to some action performed on the system?
How does it jump, erratically, or does it jump to a specific location?
If it is USB have you tried a different port? If it is wireless, could anything be interfering with the signal?
Have you cleaned the movement detector lately?