Just yesterday my audio stopped working. Seemingly from nothing. I updated some drivers with DriverScanner, but it didn't make problems immediatly (and not after reboot). I tried downloading drivers from the HP website, tried with HP Recover Manager, tried deleting drivers and letting the system download them and tried to recover the system to a point, where I did not install drivers via DriverScanner. With all variations I had 2 possible outcomes: there was audio on the notebook speakers (but not on headphones or external speakers) OR with other driver variations I had to switch off the internal speakers, and I had sound on external (but not all apps had sound, for example: I had sound on the browser, but not on skype or games).
I just hope you can help me, cause it is unbearable to sit in a silent room for so long.
Btw, I have about 17 other drivers out of date (as DriverScanner tells me), but even updating them all did not solve the problem.