It was Wednesday morning. The night before SuperDuper smart updates at it's regularly scheduled time, and Apple update runs. I haven't updated to 10.5.4 yet. Check all the boxes, close all open programs, update. I slept well that night. Walking into my office that morning the screen was dark as normal. Repeated presses on the keyboard, nothing. Unhook USB, power, rehook, hit keyboard several more times, blank. Frustration, hold the power button and let it cool down.