Neither beta will run.

I still can't launch the beta from my desktop. The toolbox doesn't work either. I can start the FPS genre kit with its own shortcut in its folder and I can start the PhysX demo that way as well, so I know that everything should work. As I've stated before, I have all of the necessary PhysX files and both my DX9 and DXSDK are updated as well. I've got .NET Framework 3.5 installed just in case. I'm running an XP system with an Nvidia 8800, so I shouldn't have any compatibility problems. Please, someone help me. I've tried uninstalling everything I can and reinstalling it about 4 times now and I'm nearly frustrated to tears.