IDE won't recognize boards in COM ports

Hey everyone, new to arduinos here doing some first time troubleshooting. First, I have a Leonardo board that I managed to connect to the appropriate COM port, but afterwards when I plugged in my UNO, it didn't recognize it and it wouldn't let me select the COM port at all, even when I tried putting it in multiple USB ports. So, I tried plugging the Leonardo back in so I could deselect the COM port, but no luck either. Any suggestions?

Sorry, suppose I should also mention I’m using windows 10

BTW I had the same problem with the Fonduino Uno, but changed the board to the Arduino Uno quickly, because the Fonduino does not support the drivers for mac...

Best.

Did you try quickly double pressing reset ?