If this doesn't work, have you been playing with the display properties in Control Panel? Make sure you haven't clicked on a second monitor (2) under advanced and then clicked on "Extend my Windows desktop onto this monitor" !!!
If I move my mouse say 2 feet to the right I have to move the mouse 2 feet back again before the cursor appears, surely the image is not that much off centre?
As it happens I HAVE been playing with the display settings but it is set to dual view, not extended screen.
I have just set it back to single screen and that cures it, but I cant see why it should disappear on dual view as it doesnt reappear on my TV screen (the second display)