Well, after trying a bunch of things I went to the local Apple Store and made an appt with a "Genius Bar" tech. Ultimately, he archived and reinstalled the OS which solved the problem (which was the first thing they concluded upon hearing the problem).
I am running OS 10.411 and have kept up on all updates. I am also having a problem opening Address Book, although my system has not crashed. When I double click on the ap icon it does that little graphic blip as any other ap does. But then... nothing. Well, not exactly nothing. In the finder...