I did some cleaning up of unused programs a couple days ago, and since then the sound on my laptop has not worked.
Product name: HP ENVY dv6 Notebook PC
Product number: C4U97EA#UUZ
Every windows-based diagnostic tools indicates there is no issue with the sound drivers.
I have tried a couple things already:
I first tried the HP Recovery Manager, to reinstall the IDT drivers. That didn't work.
I then uninstalled the IDT drivers in Device Manager, restarted, then reinstalled again from the HP Recovery Manager, then restarted. This worked initally, but the sound stopped working again shortly after.
Since then, when it stops working, I have sporatic success by going in to Device Manager and Disabling then Re-Enabling either the IDT drivers or the speaker devices.