Checking the version of DirectX
To check which version of DirectX is on your PC using the DirectX Diagnostic Tool, select the Start button and type dxdiag in the search box, then press Enter.
In the DirectX Diagnostic Tool, select the System tab, then check the DirectX version number under System Information.
The first time you use the DirectX Diagnostic Tool, you might be asked whether you want to check if your drivers are digitally signed. We recommend that you select Yes to help ensure that your drivers have been signed by a publisher that has verified their authenticity.Source: Checking your version of DirextX