I was going to ask - but have now managed to fix it....
After updating all the drivers on my Acer laptop, drivers as recommended by IObit, whilst attempting to fix an irregular crash of the OS, the mouse pointer would move fine for three seconds, stick, then move again - rinse and repeat.
I downloaded and installed one by one, the latest drivers from Acer. I got as far as the last but one driver in the list, the video driver, which fixed the mouse movement problem. The crashing Win 10 also seems to be fixed too.