Update! After threatening the laptop with defenestration, I turned off selective boot, rebooted, played spider solitaire for an hour, and told it to do the online SP1 update. Son of a *****! It took. I don't know what was the problem, but it isn't there now. Oh, 2 days ago, I did run spinrite on the HD. No bad sectors. So, as a famous actress/comedienne once said, "NEVERMIND"!