Dell XT2: crazy mouse

Have Dell XT2 with W7 RC1 on load from Dell for demo purposes, to show the touch & multi-touch capabilities. However, when typing or not even touching keyboard, the mouse will suddenly 'jump' to top right-hand area of screen and click, thus closing any doc/email/app/browser window - that I'm currently working in (this is 3rd version of this post - closed 2 others already in same fashion before got it submitted). I've calibrated, reinstalled Ntrig (?) drivers for multi-touch - nothing. Thought it could be mouse pointer (blue thing in keyboard) but don't know how to deactiveate. HELP.