I just had a problem with my 3 dollar mouse (2 years old), took it apart, took the hair, and dust bunnines off of the light sensors (i have a ball mouse, but i belive that all mice use some sort of light to see when they move, well that's the area i cleaned up).....runs like new now...it used to jump, and not move at all, but hey i thought that the 3 dollars was finally gone....