A friend asked me to look at his Gateway DX4640 desktop. When he presses the power button, power goes to the mobo (NVIDIA nForce 630i MCP73PV, GeForce 7100 chipset) and the CPU fan starts spinning. The power button slowely blinks on and off (blue) and the screen briefly says no signal and then goes black. And nothing else; no post code beeps.

My initial two conjectures were: 1. Vista was stuck in sleep/hibernation mode, or 2. A power off had left the mobo in a bad state.

The fix for both is to: a) Unplug the AC power cord b) hold the power button for 30 second to fully discharge the mobo

It didn't help. I left the system unplugged from AC power for an hour. No change.

I am out of ideas. Has anybody seen anything like this before? What does a blinking blue power button mean? How can I get more data points to guide trouble shooting?

--Thank you, --Mike