It's on a fresh Windows install (happens on almost all versions) and I haven't installed the motherboard chipset driver package yet. Of course if the card is bad, that will happen too.
As to the Realtek driver, I never use anything but the drivers from the sound card maker otherwise I find myself losing time.
I have a OptiPlex 780.I installed PCI and PCI express 5.1 audio Card.The driver disc would not download "Due to the fact that your computer is not equipped with our audio chip you cannot avail yourself to these features." I downloaded Realtek 64 HD driver. it dose not show up on my program menu but is listed when I go to window setting apps uninstall.