Hi guys, had the same problem but fixed it.
1: Open control panel
2: Click on Tablet PC Settings
3: Click setup (configure your pen and touch displays)
4: Touch the top screen twice, press enter*
5: Touch bottom screen twice, press enter (will register as touching the top screen, ignore)
6: Should work again!
Took me a bit to realize I had to click there, with the whole "pen" thing.
*An external keyboard is good for this part.
Hope this helps
