I recently tried to play Diablo II for Vista. It installed, updated and worked without a problem. Today, I'm getting Error 25 Cannot initialize Direct3D. Now I've noticed that my Windows Aero effect is not working either. I cannot initiate DirectDraw which previously worked. I've got an nVidia 8200. It came standard with the Acer X1200 Computer. I reinstalled DirectX 10 and also updated my graphics card to its newest version. Any idea why all of a sudden these effects have stopped working?

Side Note: My graphics card had a rating of 3.4, then I reran the test and now it's 3.0.
I'm kind of confused...