Not enough information to remotely offer ideas.
Fair comment, what else can I add that would be helpful?
Microsoft is pushing all kind or active and push tech. Have you noted new small info windows floating on your boot screen?
Also go to you tool bar right click on it and look for “News and interests” set to off.
If you haven’t gone this yet put a piece of tape over the camera and use device manager to disable you camera and Mic.
It could also have been a browser window that stalled closing and kept running hence the sounds.
More importantly do you have a cat?????? (= ФェФ=)