OK, I think I have come to the conclusion that it might not be the keyboard at all, at least not specifically. Since I don't do any computing on the weekends for the most part, and I was in Dallas away from my PC, anyway, I figured it would be a good chance to rest the ailing joints and start anew on Monday. Well... I woke up this morning, and my knuckles still hurt just as they did last week, so it seems there might be something else going on here. If it continues this week, I may have to go see a doctor.