The client had pulled the power cord out of the wall, one of those "high density, high resistance air connections," and wondered why the machine wouldn't start.
I had them follow the electrical cord, power supply, the thing you plug into the wall, from the back of the computer to the power strip. Then, I had them follow the power strip cord around, and it was plugged into itself. I calmly suggested that it would work better if it was plugged into the wall.
It's true and it's not the first time...