Win 10 x64 Dell Inspiron desktop PC

When I plug in a stereo plug into the Mic In on the back of the case _usually_ I get a pop up prompt of: "What did you plug in: Microphone or [something] sound center?" with Microphone already ticked so all I need to do is click OK.

I am having stereo Audio In issues [more in another thread]. I have a cassette player connected via a RCA to Stereo Plug cord. I was recording In using the Stereo plug in the Headphones jack - several stereo Left and Right Tests until I found one with not too much 'middle' and was swapping the RCAs from In to Out and putting the stereo plug back into Mic In. I am finding that after doing it twice the system is refusing to detect the plug and I have to do a Restart. I looked online to see if there was a way around this and in Win 7 and earlier there was but nothing current [when will they remove out dated info - I started following one idea until they wanted me to tick a box no longer there - sigh!]

Is it set to ignore anything put into the jack after 2 or 3 times or some nonsense? There is a minute or more between times so it should be ready.

Thank you for any light shed on this.