This is the second time I have seen this, but this time it happened to me:
The power switch started to misbehave and try to power off the system, even when the BIOS was trying to recover! I almost waste my motherboard.
My temporary solution is to cut the cables to the switch, and peel their tips. Now I start the computer joining the cables or touching them with a screwdriver. It feels like hotwiring my PC.
