From Microsoft -
http://support.microsoft.com/kb/179113
If you experience issues in which an application fails because any of the following files are missing, you may be able to resolve the failure by running the DirectX run-time package installer on your system:
-D3DX9_24.DLL through D3DX9_43.DLL
-D3DX10.DLL through D3DX10_43.DLL
-D3DCompiler_33.DLL through D3DCompiler_43.DLL
-D3DX11_42.DLL
-D3DX11_43.DLL
-D3DCSX_42.DLL
-D3DCSX_43.DLL
-XACTENGINE2_0.DLL through XACTENGINE2_9.DLL
-XACTENGINE3_0.DLL through XACTENGINE3_7.DLL
-XAUDIO2_0.DLL
-XAUDIO2_1.DLL
-XAUDIO2_2.DLL
-XAUDIO2_3.DLL
-XAUDIO2_4.DLL
-XAUDIO2_5.DLL
-XAUDIO2_6.DLL
-XAUDIO2_7.DLL
-XAPOFX1_0.DLL through XAPOFX1_5.DLL
-X3DAUDIO1_0.DLL through X3DAUDIO1_7.DLL
-XINPUT1_1.DLL
-XINPUT1_2.DLL
-XINPUT1_3.DLL
To download and install the latest version of the DirectX run-time package, follow these steps:
1) Go to the following Microsoft website:
http://www.microsoft.com/en-us/download/details.aspx?id=35
2)Follow the steps on the website to download and install DirectX.