I've got this pb on my home pc. Its a phenom x4 955 BE 6 gigs or Ram, Hd6950 and 1 TB hdd. The problem is with d3d9x_43.dll. From time to time i get this error stating that this dll is not designed for my OS or something. It doesn't just appear when playing games but it appears also when loading some internet pages.
I've had a look into it on various forums, deleted the file, re-installed directx from microsoft or other sites. The error keeps surfacing. I can play games, most of them actually but for some, like dirt 3 or ssf4, this error appears, can't play them.
I really wish i could solve this problem without re-installing the OS.
Believe me i've spent hours trying to solve this problem an still got out nothing.
Did you install directx from microsoft's web installer or by using the full runtime installer? I've heard of instances where the full runtime fixed the problem where as the web installer didn't. I'll provide links to both.
Swapnil99pro give you best advice.
After update your DirectX open run command box.
And type dxdiag - and check out of date or drive does not match with your system.
Update anything with that warning check next to it.
Clean file with ccleaner is good idea too~