Windows 7 Black screen + White Pointer after exiting ANY fullscreen program?!?

So, it seems that after exiting ANY program that runs in full screen, I'm getting a black screen and a mouse pointer... and that's it. I noticed this first after running Media Center, but it happens when I tried the MAME video game emulator, and several other programs as well... I run it, I close, and it's a black screen from then on.

The only way I can bring the desktop back is to hit CTRL+ALT+DEL, which brings up the bluish menu screen for "log out, switch user, shut down, task manager"... then logging out and back in again. Selecting "Task Manager" on this screen just brings me back to the black again.

Using an ATI 3650 card and either the beta driver package, OR the MS supplied ones, from Update seem to do this. This is on an otherwise clean install of Win 7. Ironically, when I had first installed it as an upgrade, it did not do this.

Also, this isn't the "black screen on install" bug. I was able to install Win 7 without a hitch, twice now. This is after everything gets installed, and I go to run a program like MCE, and then close out of it. THEN this happens...

I will probably be opting for re-installing Vista 32 at this point... but before I do so... has anyone else had this happen, and fixed it somehow?