Look up TOUCHFREEZE (it's free) and if that's unacceptable disable the trackpad and use an external mouse.
On my Dell laptop all of s sudden I would type a paragraph, email , wordpad ,doesn't matter what program, and in the middle of a sentence you look up and it has stopped where it was suppose to be and has gone to another sentence and inserted itself wherever it wants. Does it repeatedly maybe 2-4 times in a long paragraph.Checked 2 computers and keyboards on control panel is same so not the problem. Please help - so aggravating to try to find where the sentence is and where it goes!! Thanks ,Sandy