Quick summary...
Dennis and I completed our remote session, and we got him squared away. Auto-import was configured, and included one folder tree on a removable drive (offline) and one folder on the C: drive in a Windows virtual Music library folder.
There were no audio files in the C: drive folder tree. Rather, there were files named ._<name>.aif which were all about 4k each. This lead me to consider that this drive was once attached to some *nix-based system, and these files were metadata of some sort. I don't know what software would have created these (iTunes? which is installed). Edit: I'd forgotten - these were the resource forks of the Apple Double file format. I suppose in some future version MC should delete these along with the matching data file (fork).
Regardless, there were no media files; they had been Deleted via MC, using standard Delete option 3 (permanent).
So there were nearly 20k Bad or Removed files in total. We cleared out these databases.
As the Windows 7 virtual library collections confuses many, we created a new music folder in a user-friendly location, outside that chimera, and reconfigured Auto-import and File Locations paths.
After copying a few music folders from the removable drive to the C: drive music folder, and after some MC analysis, the views started populating as expected.
I demonstrated how to use MC's Copy/update mode to make copies from the removable to C drive.
As an aside, one cause, as expected, for apparent MC sluggishness was that AVG antivirus was (over-)loading the system. We configured it to ignore MC programs and music folders. It was producing ~ 3k page faults/second. Much snappier when it was told to mix out.
Its always valuable and interesting to become reacquainted with a new(er)-user perspective.
Kudos to D.H. for working through the curve.