Wow ... what a suite of tests. All tests passed. I didn't run the extended memory tests yet, because the message said it would take 30 minutes, and I don't believe this has anything to do with memory (no such symptoms).
I thought it's possible that the Bluetooth light is simply defective, but that wouldn't prevent Bluetooth from working. When I try the Bluetooth settings, it simply tells me "No devices paired." And that's because there's no way to pair any.
Dongle is arriving today, so maybe that will solve everything. Thanks, both of you, for all the help.