Well, I discovered on my own that it was "Google Updater" that was causing the crashes. I looked in the logs and exactly one second after this program started, the PC crashed. It was not old drivers, but it was a good chance for me to examine my drivers. Thanks for the help!
(Now I am playing with my new toy, an Ubuntu laptop. Ubuntu is not quite the Windows killer the fanboys say, but it's getting close, real close...)