If you get errors while trying to launch a game (like d3dx9_43.dll ), you need to update DirectX.
How to Fix Missing DLL Errors: Download DLL Files for Windows 7 32-Bit download dll files for windows 7 32 bit
These files can be bundled with spyware or trojans. If you get errors while trying to launch
Dynamic Link Library (DLL) files are the unsung heroes of your operating system. They contain code and data that multiple programs can use simultaneously, saving memory and disk space. However, when a DLL file goes missing or becomes corrupt, your favorite apps and games will refuse to launch, usually greeting you with a frustrating "The program can't start because [filename].dll is missing" error. They contain code and data that multiple programs
Windows 7 has a built-in "doctor" that can often repair or replace missing system DLLs automatically without a manual download. Click and type cmd . Right-click cmd.exe and select Run as Administrator . Type sfc /scannow and hit Enter.
If you absolutely must place a DLL file manually (perhaps for a specific piece of niche software), you must put it in the correct folder.