Fix d3dx9_30.dll Missing Error for Resident Evil 4 - Easy Solution
Do not, under any circumstances, download d3dx9_30.dll from any "DLL download site". There are a number of reasons why downloading DLLs like that is never a good idea. If you already have, remove it from wherever you put it and continue with the following steps.
Several users managed to fix things when d3dx9_30.dll was missing by downloading the DirectX End-User Runtime Web Installer. Even Microsoft recommends the solution in its official blog on the missing DLL error.
d3dx9_30.dll download resident evil 4
In most cases, simply uninstalling the application throwing the error, and downloading it all over again will help if the DLL file is not found. This especially works when d3dx9_30.dll is missing in Windows 10 and the latest iteration.