I have similar problem. Somehow I lost the VIA deck (or what ever it's called), so I decided to reinstall the latest drivers. I uninstalled all the old ones and tried every VIA driver there is, but all I get is an error which says that some elements were not installed, install failed. So now I'm running the default Win 8 Microsoft HD drivers, but I need my EQ settings.
No idea how or why the old VIA drivers broke down or why none of the available drivers can't be installed. I just can't figure out why I can't install any driver. I even tried to uninstall the default HD drivers and the tried to install VIA ones, but no game.
Any ideas? Can it be the nVidia drivers as I installed the new 320.14 beta drivers and I think the VIA deck got "lost" after I rebooted my laptop after some days after that.
G75VW
OS: Win 8 Pro 64bit
EDIT: I tried those driver's from c_man's thread and I get the same error:
Fail to Installed components :
VIA HD Audio Codec Driver v10.6.00.30.120710
And then "Some components couldn't be installed, check the log", but I can't find any via install logs.