please help while i installed 8 pro vl two weeks ago, Mic was working I installed 8 pro retail yesterday ,Mic not working in both case, i tried sound recording right after installation. checked sound setting, in 8 vl, all drivers were nvidia hd audio, in retail version, its all microsoft hd audio. tried to reinstall nviadia driver, didnt work
you need to run the original drivers for you board/soundcard. Legacy drivers coming from MS are not working for many cards unfortunately.
Would be good to provide some info regarding your sound solution. As described i guess it´s an onboard soundchip. As Paul stated, install proper drivers for it. Nvidia HD Audio normally is installed by Nvidia Forceware Drivers. For me (GTX 570) there are 4 entries for these in Device Manager, but the important one is Realtek Audio Driver, i had to install seperately.