Microsoft bus driver error message

A coworkers computer has no sound. I checked device manager, did a webchat with the pc manufacturer support. They gave me a link to the drivers for it on their site. I download and try to install, but get a message saying, "microsoft bus driver should be loaded in your system before installing realtek audio driver". I see many posts all over the place regarding the QFE mentioned here: http://couponmeister.com/blog/HD_Audio/KB835221.exe

I have tried that hotfix with no success. That hotfix tells me the SP (3) I have on this machine is newer than the hotfix, hotfix not needed, and closes out without further option in the matter. I read somewhere else to update the chipset drivers. I've done that with no success. Anyone have any other ideas? Or is this guy SOL?

Thanks,
Lori