i had same problem,
i had ghosted a scenic onto an esprimo and four drivers were different:graphic, Lan, the one you have missing and the HD audio was partially missing or corrupt.
i checked on pcidatabase and found some info but not enough.
even though the pcidatabase site was saying it was an intel driver, after i installed the realtek hd audio the unknown driver issue went away.
turns out it was the ' intel high definition audio HDMI service ' driver which is bundled with the realtek hd audio.
go to the manufacturer site for your pc and download the hd audio and/or chipset drivers.
hope this helps