Unable to play game after installing Direct X 11

Hello,

Operating system Windows 7 has been installed in my system.  I installed a game and it was running perfectly fine on my PC. Then, I installed the Direct X 11 on the system. After this, I am having a problem while playing my game.  It was working perfectly fine before, but now, I keep on getting the following error on my screen:

'Setting Fail: Direct X device error'

My game is continuously crashing and I am not able to play it at all.

This happens when I am playing with my old characters. I started a new game with a new character, but I was unable to even purchase the skills for that one. The Ok button was not highlighted. So, I couldn’t  press it.

I tried by all means to resolve this issue, but I failed. I posted this problem to many forums. I found a solution on one of the forums, which was to force re patch the game. Following these instructions, I deleted the files and then tried to upload the game again, but the same Direct X device error  is seen on my screen.

I have tried to reinstall the game by using different downloading softwares, but the problem is still there.

I cannot figure out  the root cause of the issue.

If anybody can be of any help to me, I'll be really thankful.

Regards.