8800GT Biostar Freeze

when i run direct3d test (dxdiag), directx 7 test is fine.
But when run directx 8 and 9, my computer hang.

But when run directdraw is fine.
When i open nvidia control panel, when i select menu "adjust display with preview" (there is nvidia logo flying around), my computer hangs too.
But when i select another menu likes refersh rate, resolution, color depth, and etc, my computer is OK.

I had tried to format my computer and installed original driver, but it didn't work.
I also tried to installed the latest driver, but it didnt work too.
Then, i also check my vga card in "device manager". In "device manager", my vga is worked well.

Now, i still use it. But if run 3d application likes 3d max, my computer hang.


my question are:
1. my vga card broke or not ?
2. if my vga didnt break, how to solve it ?