Vista 64 Alt-Tabbing back to desktop not so randomly..

[llPANCHOll]

So often when I find myself in an engagement and am hitting several keys and mouse buttons at the same time I am sent right back to desktop and by the time I get back to the game, of course I am "Wounded" or "Killed"....

For some reason I think it is the Middle Mouse Button that is the culpret, but I cannot be sure....

I dont think I have any mouse jestures programmed and have looked to try to turn them off if they were enabled.. I use a G5 mouse and a G15 keyboard.. any help appreciated.