Hi,
1. What is the exact error message/code that you get?
2. Which version of Direct X did you try to install?
Check the DirectX version in the Computer by referring to this article:
http://windows.microsoft.com/en-US/windows7/Which-version-of-DirectX-is-on-your-computer
Some applications and games require DirectX 9. However, Windows 7 is installed with a more recent version of DirectX. If you install an application or game that requires DirectX 9, you might receive an error message, such as: "The program can't start because d3dx9_35.dll is missing from your computer. Try reinstalling the program to fix this problem." The last two digits of the file name might vary. If you receive the same error message after reinstalling the application or game, go to the DirectX End-User Runtime Web Installer webpage and follow the instructions to install DirectX 9 and receive updates to DirectX 9 and previous versions of DirectX.
Also Refer:
Diagnosing basic problems with DirectX
http://windows.microsoft.com/en-us/windows7/Diagnosing-basic-problems-with-DirectX
Refer the article on how to fix Game performance issues:
Fixing game performance problems
http://windows.microsoft.com/en-us/windows7/Fixing-game-performance-problems
Let us know.