I am experiencing something very weird on my Compaq Presario 720US which is running Windows XP Home with SP2. The firmware is current (version F0.C). My problem: at random intervals, something takes control of my cursor and sends it to the upper right-hand corner of the display, whereupon it does a series of left and/or right button clicks. If your current window frame is maximized then that frame gets closed - terribly inconvenient as you might imagine.
More data: latest Norton reports no viruses.