Recently two of my relatives complained of the same maddening problem: They'd be typing along on their laptops when suddenly the cursor would jump, resulting in garbled text or even an unwanted mouse-click.
This is usually the result of your thumb or palm accidentally grazing the touchpad. Fortunately, there are ways to combat this problem, usually by tweaking Windows' mouse/touchpad settings.
If those options aren't available on your system or you're still not getting the results you want, try TouchFreeze. This free utility serves one simple purpose: to disable your laptop's touchpad while you type.
Actually, it disables touchpad tapping, which is what causes the aforementioned problems. (It doesn't matter if your cursor moves while you're typing, as long as that movement isn't followed by a tap--the touchpad equivalent of clicking a mouse.)
If you've been tearing your hair out due to flaky laptop behavior, this handy freebie may just solve the problem.