Well, it seems as though this is a 5-month repeating problem. I've gotten in the practice of shutting down the computer overnight about half the week, but suddenly this evening, she froze up on me. During reboot, I saw the same error message upon attempted controller detection, and the system behaved exactly like it did back in May. So, I waited until late evening when my wife went to bed, and then I shut down the computer, disconnected it, popped the top, removed as much dust that I could over the course of an hour, then replaced the cover, reconnected, and started her back up again. Once again, the system detected the controller and drive. Problem solved... or should I say, symptom suppressed.
Later!
