I need help with DirectX....Im not sure what to do...

I have recently redone my computer...it was full of trash that i couldn't get rid of...anyway after everything was reinstalled I installed a game and it required an update to 9.0 so i did. But now its saying i don't have Direct3D. I've tried looking up info on it and nothing has helped. I've tried reinstalling 9.0 from microsoft's site but that didn't work. so i thought maybe something didn't install right when i reinstalled windows...so i tried reinstalling the drivers and applications...but that didn't work. im worried im messing my computer up. Does anyone know what to do? I hope im in the right place...if not I'm sorry i didn't know...some forums have strict rules about what can and can't be said or asked in certain places.