Ok, I’ve troubleshot this thing to death. I’ve discovered that it’s a bad processor, not the motherboard. Which means I’m screwed because the processor was a christmas gift, and is past the 30 day service policy on OEM parts.
A huge thank you to Jason Smith for spending over an hour troubleshooting with me, and to all of you who wrote in to try and help.
I’m going to bed. I’ll figure this mess out in the morning.