Thank you, gentlemen, for all your assistance. Unfortunately, I am still having the same problem. I have noticed that the hardware number in the "pan1" description keeps changing, which I find very interesting since it looks like a MAC address. I didn't know they changed like that. (Have I been infected? And I have been so careful.)
I loaded "Timeshift" and created a backup. (I know. Closing the door after the horse has already left.) I am wondering if I can timeshift one part or if it's an all or nothing for that saved time slot? Like, say, after a reinstall of Mint.
I did go back through the history using Synaptic but did not see anything that would have caused the problem (Unless it was an update). I even reinstalled all the named removals I had done, to no avail. When I tried to reinstall the network manager, it told me it could not get a lock on a folder because I did not have the proper authorization to do so. That seems strange since I am the only one on this computer. (su needs a password which I can't find and do not remember setting up when I installed this version of Mint. sudo works fine.)
Is there a way to start a terminal in "root"? I know, it's dangerous but right now, what's the worst that could happen? I could destroy my Linux and need to reinstall it, right?
So here I am, stuck in the middle, wondering what to do next. I'll keep plugging away until I find an answer that works or I completely trash my install. At least with Timewarp, I can jump to the left and a step to the right, and maybe get back to where I am now. But if you have any other suggestions, I am willing at least to listen and say thank you.