How to Fix d3dx9_38.dll was not found error?

Kevin asked us the following question:

Whenever I try opening Fallout New Vegas which i had previously installed on my PC (running Windows XP) I am getting an error that says “d3dx9_38.dll was not found”. What should I do to fix this missing dll file?

Thanks for the question, Kevin. This error message appears because of a corrupt DirectX installation or due to missing files in the DirectX directory. I would strongly recommend you to download and install the latest version of DirectX. We don’t recommend to download d3dx9_38.dll or other DirectX dll from a 3rd party site.

After installing, restart your PC and try opening the game again – everything should work just fine now!

Note. Windows XP is known to show this error for many users. Running Windows Update periodically and making sure you are on the latest service pack (in this case,  SP3) usually help preventing missing dll errors.