Thank you for both these suggestions, which I tried.
The issue with both is that the only devices showing up are:
Realtek HD Audio (default). I think this is the inbuilt mic
ManyCam Virtual Microphone (I installed ManyCam for the visual tricks it can do).
There aren't any of the headsets I have, (which range from a Logitech USB set to a Sennheiser audio socket set and others) listed, even if I have one of them plugged into the computer.
This problem occurs with both the Control Panel's Sound thingy and Audacity's microphone choice dropdown.
Please help because I want to record an asmr "Whispering" youtube video. My subscribers are nagging me for more. (I'm muskndusk). Here's me, WARNING, you might fall asleep:
https://www.youtube.com/watch?v=D2cD0dzS9kw