Well, it went back to the Geek Squad today. At first it didn't run, then it ran, then it didn't run, then they sent it back. Presumably it will come back with a new battery and a complete diagnostics workup.
Meanwhile, I've been in a kind of a haze all day. Granted, it was rainy and dark, but I never seemed to wake up. I think I could have used a third cup of coffee. I ended up dozing this afternoon, and I'm ready to climb back into bed.