I would be looking at the touchpad as the cause. I had a laptop with this and it was a pain in the a** for causing strange things to happen. I started using a little portable wireless mouse and that solved the problem.
Open up notepad, and save it somewhere.
Type sdlkfjsadlfk, and copy it. Then start pasting it, paste it several times. Just press Ctrl+V, and hold it for a couple seconds.
Now, Click File>Save, and watch the cursor carefully.
Nope, not here. Works just fine.