Unwanted Final Signals on Touchpad

Apparently the touchpad on my Dell XPS M1210 (as well as on the previous model, Dell 710M) responds to finger signals in Outlook and Word (and probably other programs). If I accidently touch my thumbs in Outlook, the message is sent. If this happens in Word 2003, the page is minimized. Does anyone know a way to turn off these unwanted finger/thumb signals?