Need help with dual monitor problem

Recently when I go from full sreen gaming (like wow) to the desktop via the windows key or alt-tab, I am unable to go to my other monitor. It was never a problem before and I changed nothing of note during the past month, but I am only able to bring the mouse to the other screen when I drag a window onto it. I have a dual view setup with an nvidia gforce 7800gtx 256mb. I messed with all the video settings I could fathom and updated my drivers, but still nothing. Any ideas?

>>8
Owned because the game the OP was playing actually had a Mac port