WOOHOO! Got it to work!

When I first ran the WhiteScreen Test file that Dylan gave me, I got a DirectX version checker error that basically said 9.0c wasn't installed. I knew 9.0c was installed (DXDiag confirmed), but that got me thinking. I decided to force a reinstall of 9.0c and wouldn't you know it, everything started working. The demo, the patches, the white screen test files... it was like magic. I played through a song (wicked fun, by the way), just to make sure I could actually play and not just only start the game, and it worked perfectly.
Thanks for all your help Dylan and lebeth!
PS: Reinstalling 9.0c is a little tricky, if anyone needs help with that, I can post steps.
PPS: I'll still be happy to test any patches (or anything you guys have for that matter), just let me know if you need me.
PPPS: I'm using the latest ATI drivers (aka Catalyst ver 8.2)
-Wuff