directX in bootcamp? (windows 7)

Hi!

I've recently installed bootcamp on my iMac, and it works perfectly, no problems with the internet or the sound, BUT when I try to install a gameit pops up a textbox that says something like;

"could'nt find any DirectX9.0-compatible graphics adapter on this computer! Check that you have a DirectX compatible graphics adapter and that you have installed the latest device drivers from the graphicscard manufacturer."

I don't know what to do, please help me!

I have downloaded DirectX and installed it several times, and it keeps saying the same thing, whats wrong?!

I'm sorry for my english, but I hope that you understand what I'm trying to say....