First, questons: Laptop or desktop? (Laptop, I'm guessing) External mouse for your hand, or integrated pointer nubbin, or trackpad?
Usually there's a sensitivity setting that can stop this, only more vigorous purposeful movement from your hand or fingers will move the cursor, or if it's an integrated mouse-device in the laptop, there might be a recalibration option to re-center it.
Although the Thinkpad/Toshiba style nubbin pointer that sits between the G, H, and B keys, those can be pushed/bent so hard they'll take a permanent set and just track in the direction they were broken forever.
