Roger, put down the screwdriver and step away from the computer.

That's really odd. So you basically shorted the button to the case with the screwdriver? Hmmm...sounds like a faulty switch. Is it metal? You might want to see about replacing it.

In a former life as an electronics tech I was once working on some circuit boards in a test rig which had all it's covers removed for ease of access. Anyway, I was holding on to the frame with my left hand and reached for the power switch with my right - a metal toggle switch. Turned out the toggle was shorted to the hot line of the power. I got a 120v zap in one arm out the other, passing through the chest (and my heart) on it's way. That was NO fun. Fortunately all I got out of it was an adrenalin rush.

BTW, the only reason I got shocked was because I was grounded by touching the metal frame. I had many times previously touched this switch with no ill effects.

Brian