I have:

Asus PC-DL Deluxe
1 x Xeon 3.06 Ghz 533 Mhz FSB
2 x 512 GB Corsair RAM
LSI Logic U160 SCSI Controller
1 x 36 GB Cheetah 15K.3
Sapphire Powered by ATI 128 MB Radeon 9800 Pro
Enermax 460W PS

After formatting the hard disk, installing Windows XP Pro, downloading all the latest updates from Windows (including SP1 and DirectX 9.0b), installing the motherboard drivers (sound, LAN, USB and Intel chipset) I try to install the ATI drivers and I get an error saying that DirectX is not installed. So I checked on the Windows update log and I see that DirectX 9.0b end-use runtime was installed without any problems. Just to make sure I reinstalled DirectX, again without any problems, but when installing the ATI drivers I got the same error again, so I just ignored it and continued installing the drivers, and the video card seems to work fine.

Then I continue to install the drivers for the ATI TV Wonder PCI, but here I get again the same warning that DirectX is not installed. Again, I ignore it and continue with the installation, but in the end I get a code 10 error - device cannot start with the TV tuner card. There are no shared IRQs, so I assume the error has something to do with that recurring message about DirectX not being installed.

I tried installing the same video card and TV tuner card on another motherboard (ASUS A7V333), also with Windows XP Pro, and I was able to install all the drivers and software without any problems whatsoever, the DirectX not installed error did not appear, neither the code 10 error.

What can be the problem? Any suggestions will be appreciated.