I've recently installed a Radeon HD 5670 in my asus mobo pc. Running W7 home premium. Previously had on-board (nvidia)graphics chip as well as realtek alc 662 6 channel sound. Video works great, but never have gotten the sound to work quite right. I've contacted Asus support and have the Bios set to their recommendation. Any ideas? I'm desperate!
Download Driversweeper from http://www.guru3d.com/category/driversweeper/
Download the latest drivers from the website for the Sound card. Don't install them now.
Uninstall the realtek drivers from the control panel from add and remove programs.
Then do not reboot, but run driversweeper and check the realtek box to clean away all the leftover traces from the rig.
Then reboot the rig.
Now install the fresh copy of the downloaded drivers for the soundcard and check.