File extension .dll is related to Dynamic System DLL Libraries. Files like d3dx9.dll are similar to the EXE file (executable). They allow you to run different programs on your system. For example, you are running Windows, and edit a document in Microsoft Word. File which is responsible for printing the text is not loaded until this is not necessary. After you select the "Print" function, Microsoft Word is called appropriate file and it will be written to RAM memory. If you want to print a document in another program, the same DLL file previously loaded into memory will be used.
What options do you have to get rid of "d3dx9.dll missing" issue.
In the majority of cases, the solution of d3dx9.dll missing issue is to correctly reinstall particular software that is using this file on your PC, to the Windows system folder, or to the game or application installation folder.
But in case you do not have the installation distributive of application or just do not know, what program is using this file – you should probably download this missing or damaged file and put it in the right folder.
The most common errors related to d3dx9.dll:
d3dx9.dll was not found
Can not register d3dx9.dll
d3dx9.dll Access Violation
d3dx9.dll file not found
Component failure d3dx9.dll
Can not find C: Windows System32 d3dx9.dll
Can not find C: Windows SysWOW64 d3dx9.dll
How to install the file
Manual installation of .DLL files directly to Windows is very simple
Copy file d3dx9.dll to C: Windows System32 folder. (32 bit)
Copy file d3dx9.dll to C: Windows SysWOW64 folder. (64 bit)