Upgraded from Windows 8 to Windows 8.1, sound doesn't work, reinstalled driver, still not working

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.

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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.

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I downloaded the IDT Audio driver at

http://ftp.hp.com/pub/softpaq/sp59501-60000/sp59654.exe

Referenced here

http://h10025.www1.hp.com/ewfrf/wc/softwareCategory?os=4158&lc=en&cc=us&dlc=en&sw_lang=&product=5327887#N267

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

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What else can I do?