I've been getting some very high heat detection (55 idle 83 load) so I went into my computer to move some cables and attach more fans.
1. I disconnected 3 cables (HDD, CDROM, external SATA port) at the device end, not at the mainboard sata area, rerouted them, and plugged them back in.
2. I tried to do that with the external audio port's connection to the mainboard, but it was stuck too firmly, even with gentle jiggling.
3. I connected IDE to 2 hard drives, which took quite a while with lots of maneuvering and moving cables.
4. I connected 3 fans in a chain to a power supply molex.. and saw blue lightning inside for a moment, realizing that I forgot to unplug the computer rather than just turn it off.
Now it won't start and I can't figure out why. I press the button to start the computer and nothing happens. Could it be a zap to the mainboard or power supply? The LED that is directly on the motherboard is still working if the power supply is plugged in (interestingly, it still works if I set the switch at the back of the power supply to off, not sure if it did that before but I think it did). Could it be the force of pulling that audio cable? Could the cable from the button to the mainboard have gotten loose? I retightened it.
This tower's power button has, BTW, been stuck in pressed mode. It has still worked up to now however.
It could be the power supply/fan failing, from the heat detection. I don't know what all you do/have installed to your machine, so wouldn't know what could tax it so. For why it's not turning on, could be connection issues.
I got it to work by shorting the power connectors with a screw, so it was related to the power button or its connection.
Well, there ya go. XD Good thing it wasn't anything worse.