Hello Officiant and welcome to Toms!
I am pretty sure I know what your issue is, so bare with me here.
First, when you are typing, do you have your touch pad enabled? Do you have a mouse that you use with the machine? Do you use your built-in keyboard or an external one?
I have seen this a LOT, that when touch-pads get old, they get VERY sensitive to heat. What I am implying is that even if you are not bumping your touch-pad, it is sensing your hand heat from above the pad, and moving the cursor. As the protective covering wares off of the pad itself, this becomes quite common. To test this theory, turn off you touch-pad in control panel, and try typing a letter.
Thanks!
- Harrison Whitmarsh
Lincoln Nebraska USA