DxDiag ("DirectX Diagnostics") is a utility designed to display the specifications of the user's hardware, as well as to test DirectX software, including sound and video. DxDiag was first released on August 7, 1998 as part of DirectX 6.0 and the successor to DXInfo. To open this program type dxdiag in the Windows Vista start menu search bar or the Run command (Start->Run...) in any other version of Microsoft Windows (see image).
DxDiag is a diagnostics tool used to test DirectX functionality and troubleshoot video- or sound-related hardware problems. DirectX Diagnostic can save text files with the scan results. These files are often posted in tech forums or attached to support emails in order to give support personnel a better idea of the PC the requester is using in case the error is due to a hardware failure or incompatibility.(See Diagnostics section below)
DxDiag by default located in %SystemRoot%\System32.[1] In Windows Vista, DxDiag only shows information; it is no longer possible to test the hardware and the various DirectX components. [2]