Maybe try these https://www.bleepingcomputer.com/news/microsoft/windows-10-audio-not-working-after-installing-latest-windows-updates/
Thanks. Just tried that and discovered this:
All of my audio devices* say 'Currently, this hardware device is not connected to the computer (Code 45). To fix this problem, reconnect this hardware device to the computer'
As I said, both the built-in speakers and the headphone jack don't work, so what hardware could be disconnected??
(I opened the laptop and disconnected & reconnected the speakers and tried blowing out any dust, but that didn't work. Anyway I'm not sure how the speakers could be the problem if the headphone port is also not working.)
In case this list helps, here are all the devices that give that message:
Intel(R) Display Audio
Microsoft Streaming Clock Proxy
Microsoft Streaming Quality Manager Proxy
Microsoft Streaming Tee/Sink-to-Sink Converter
Microsoft Streaming Tee/Sink-to-Sink Converter
Microsoft Trusted Audio Drivers
Realtek High Definition Audio
The only one that was showing as connected was Microsoft Streaming Service Proxy but as I was typing this message that also changed to giving the same 'not connected' message in the properties window.
Any ideas?? TIA for any help!