Tablet Screen Orientation

Hi, I have an Acer TravelMate C200 which I just installed Windows 7 on it. In Windows XP Tablet Edition, I could change the orientation of the screen just by tilting it the way I wanted. I would have the lid closed and prop it up and the orientation would change. Ableit it would BSOD me half the time, but it worked. Now however, it just goes black until I put it right and open the screen. It's not going to sleep or hibernating, because I turned those off for lid closing.

Any ideas?

I'd be happy if I could just find a way to disable the automatic screen rotation