The DXDiag is a diagnostic created on Windows that gives information about your computer and your GPU setup.
Here are the steps to export it when requested by the support team:
- Go to Start > Run and type "dxdiag" (without quotes) in the "Open" field and press OK button
- Wait for the "green" progress bar to finish loading and then press the "Save All Information..." button
- Name the file with some useful info, like your name and the date, and save it where you can find it, like the Desktop, by pressing the "Save" button
- Press the "Exit" button to quit this application