Airymouse, your situation is my worst fear. I'm sorry you've lost your sound.

Too bad we don't have System Restore any more.

Just to give you an idea of how quirky computer sound systems are: any time I click on a link to a program on BBC radio and listen to it, I've found that my MIDI does not play. I could get Noteworthy Composer to work by shutting down and restarting, but I shouldn't have to do that. (I no longer listen to anything from the BBC.)

If the BBC can screw up my system with a radio broadcast, what might Windows 10 do? And surely it won't be so easy to fix.