Have you had the laptop in an environment where debris (especially conductive debris) could have got into the keypad gaps? I have seen similar symptoms from a laptop that had been used in a workshop and a couple of tiny nails had got lodged under the keys. They were not visible but their effect was very much as you describe.
think I now agree that vpn is not the cause of the cursor jumping, but now I have unticked the vpn box on the startup (msconfig)the screen is not jumping around - but the cursor is. 5 times in this short paragraph
Check to see if you have "tapping" turned on. - control panel - toucpad settings - advanced (i think) see the fault quite often people accidently tapping the touchpad as they type - often don't realise they are doing it - the carot that automatically jumps to the cursor - as the tap on the touchpad acts like a left click. IF this doesn't solve it i'd reccomend new touch pad.