I have an HP Envy dv6, Product number: B6C68AV.
I had Windows 8 Pro 64-bit running on it just fine. Last month I upgraded to Windows 8.1 Pro 64-bit and my sound doesn't work anymore. If I go through the "Find and fix audio playback problems" winzard in Windows most of the time it will fix the problem, but I have to do that every time I reboot or wake the laptop up from sleep. When the fix works, it says it made my sound device the default and that fixed the problem.
So then I think I just need to set my IDT device to be the default, but when I go to manage my sound devices it says there are no audio devices installed, so there's no way to set one of them as my default.
I downloaded the IDT Audio driver at
http://ftp.hp.com/pub/softpaq/sp59501-60000/sp59654.exe
Referenced here
but after installing and rebooting it still doesn't fix the problem.
Here's what HP Assistant says I have installed in terms of audio drivers
What else can I do?