The sons laptop which used to be mine is a compaq presario c700 has always worked fine with no problems until now.
The pointer zips around the screen without touching the mouse pad and stops if i switch the mouse pad off and starts moving again by itself when i switch the pad back on its like using a finger on each hand moving in different directions on pad.
you may need to recalibrate your touchpad (there might be some kind of utility installed) you may need to reinstall the drivers. It may be a knackered pad, and you will have to disable it and use a mouse instead.