Screen rotation hot key (Ctrl+Alt+Up) not responding, what's going on?

Question

The other day my son (11 months) discovered a new hot key combination on my laptop. As I'm sure many of you are aware (I wasn't until the other day), on machines with Intel Graphics, pressing Ctrl+Alt+{arrow key} rotates the screen. After I recovered from my shock, and did a little sideways Googling to figure out how to fix it, I decided this might actually be useful. I read a lot of online documentation, and it fits better on the screen when it's rotated. Since it's a laptop, I hold the machine like a book and read it. It worked great all afternoon yesterday.

But today at work I tried to show a friend this new trick, using the same laptop, and found that the Ctrl+Alt+Up no longer works. I can rotate it to any orientation but the normal one. I'm guessing something else is intercepting this hot key, but what could be doing this?

Answer 1

Also had the problem of non-working default keys once, I think on a notebook with intel GM855 something chipset. I believe it was this tool that solved the problem form me: iRotate http://www.entechtaiwan.com/util/irotate.shtm

Answer 2

The mouse cursor has to be on the screen you want to change.
After you make a change, the cursor always defaults back to the primary screen.

Answer 3

It can also be disabled via group policy, which is something a lot of IT departments do as a matter of course in an environment where there are no tablet pcs.

Otherwise, you get occasional frantic calls from people who've rotated their screen 180 degrees and are now helpless, and trying to work with their monitor flipped sideways.