About once a month I get a phone call from someone who claims that there is a problem with their computer. The problem shows up when they are typing something usually in Microsoft Word or typing an email. They claim they are typing away and suddenly the cursor jumps and goes somewhere else on the screen.
Nine out of ten times this is the solution to the problem they are having. When they are typing they rest their wrists on the laptop. Their wrists touch the track pad and this in turn causes the mouse to jump. Either that is what is happening or it is their jewelery that is dangling down and touching the track pad.
To test this out try turning off the touch pad and typing something. You can turn your track pad off with either a small on/off button near the track pad or a combination F key will turn it off. Google your make and model and the words “turn off track pad” if you can’t figure it out. You could also try using an external USB keyboard.