At least the INF drivers have to be installed.
Then check in device manager if it shows your sound card or an unknown device. If it does, then maybe you just need the drivers for your sound card. I am having trouble finding the manufacturer's website of your sound card. Does it support Windows 7?
You can disable the onboard audio chip in BIOS.
Try the other PCI slot. If you have another PCI card in your system then try testing without that card.