Just a thought, and this might sound silly, but I had the exact same problem when I first purchased a laptop a few years ago. I complained to the shop and with a wry smile the guy said that I should make sure that I kept my hands well clear of the touch pad while typing.
When he mentioned it I thought he was daft and that couldn't be the problem. But it turned out as I paid more attention to what I was doing with my hands whilst typing that sometimes they (or a sleeve) did drift across the touch pad and send the mouse cursor careering off somewhere else.
Don't know if this helps, but it was what was 'wrong' with my first laptop (an error between the keyboard and the chair)!