About 3 weeks ago I started having strange behavior on my computer. Web pages suddenly scrolling to the bottom of pages, cursors moving all the way to the right of a box, the play/pause icons in VLC flashing on and off and video not playing correctly. This only happened intermittently. The keyboard is a Microsoft Ergonomic Natural 4000 on a Win 7 pro 64 system. I changed the mouse and still had problems. I then changed to a different keyboard and had zero problems for a week. So I ordered a new keyboard exactly the same as the one I thought was bad, and as soon as I plugged it in the problems started again. The same exact problems so I tried different USB ports which had no effect. I just changed back to the different keyboard and no problems again. Does anyone have any clue as to what may be causing this problem? I hope its not a motherboard.