I am running Vista Ultimate with directx 10. My video card is compliant with and supports directx 10 as does my sound card. Do I have to install the directx 9.0c that comes with Chessmaster 11 in order to get it to run? So far I have not been able to get it to run on my machine. I did not install directx 9.0c. I was afraid that this would screw up my directx 10 installation.

Yes, install DirectX 9.0c. It won't hurt anything with your DirectX 10, as they're separate DLLs.

Hope this helps!

Thanks for the advice.