Hi Riddle,
I am having exactly the same problem on my HP Pavilion X360 m Convertible laptop, Model 14m-cd0001dx. I tried the steps you outlined above, but it did not fix the no audio problem. As the original poster stated, this started just recently after the October 2018 Windows Update.
I do not have an "Intel Smart Sound Technology" driver in my Device Manager but I do have a "Realtek High Definition Audio" device in its place, so that's the one I uninstalled/deleted. Still didn't fix the problem. When I go to the Sounds settings, everything looks like it should be playing audio, but nothing comes out of the laptop's speakers. The microphone works just fine, and if I try a video chat, the person I'm talking to can hear me...but I can't hear them of course because I have no audio.
Please let us know ASAP what we can do to fix this problem. Would doing a System Restore to before the Windows Update possibly fix this, at least temporarily? Or is there somewhere we can manually download and install an older version of the audio drivers? Thanks in advance!
EDIT: I figured it out, found the solution on another post in the forums. For the record, here's the solution that worked for me:
What I did was to go the original website of Realtek, here :
http://www.realtek.com/
Choose downloads > High definition audo codecs (checkmark) > and choose the 64 bit driver at the top of the list.
I went into Device Manager, uninstalled/deleted all of the audio drivers there and then installed the one I had downloaded directly from Realtek. The installer made me reboot and once the laptop came back up, sound was working again. Voilà!
