In order to enhance the performance of a computer, especially the audio and the video for certain applications such as high-end PC games, DirectX is required. DirectX comes as a part of the operating system and it is easy to determine the version of DirectX is which is installed on Windows. One simple command will provide all the information related to the installed version of DirectX. Run the command on the command line to determine the version of the DirectX which is installed on Windows. If the OS is Windows Vista, the latest Directx10 for Vista should be installed, for better audio- video performance while playing games.