i can't install directX 9.0c

even if i install directX9.0c and restart my computer i look at the dxdiag and it is still directX 9.0b, i checked the DirectX files there's a problem "the file qasf.dll is an old version, which could cause problems" and there's a message below it saying i should reinstall DirectX to get the latest version, but i reinstall it with 9.0c and still no use..
can anyone help me how to succesfully install the DirectX9.0c, tnx in advance

Try installing it in while in safe mode.