I am astonished at the response I got to my little problem– over a hundred emails from hobbyists to people at M.I.T. Nearly every email was helpful. Unfortunately, I can’t thank everyone personally (I tried, though) but for everyone who emailed in to help, I am extremely appreciative. I’ll try a few things, but consensus seems to be it’s a bad motherboard controller, which is not cheap to fix. C’est la vie…