Can install, but not play?

I can download GW onto my computer but when I try to play a get a message popping up saying...
"C:\Windows\system32\d3d9.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support."
Now I recently formatted my computer and before i formatted it I was able to play GW without a hitch. Now, I can't even play it...
Any help?

Looks like a directX file - try reinstalling or repairing DirectX (9c or higher).