Guessing here, but perhaps the directional ball on your mouse is dirty.
Somebody please help. I am running Windows XP SP1 and my computer kinds of gets still for half a second every 4-6 seconds. So whenever I am typing it misses a character or two every 4-6 seconds. When I am moving my mouse it gets stuck at a position for a second and then gets back to normal. This keeps on repeating.
Any directions would be appreciated.