System was working great for a week... until today - now it powers on for about 5 seconds and turns off, then repeats this forever. Never any video when I did have a GPU installed - removed it and all other devices for troubleshooting.
I've stripped it down to just mainboard, RAM, and CPU. I've noticed that when I first switch on the power supply, a little orange LED labeled "FBIOS LED" between the USB connectors turns on for about 2 seconds and then gets very bright before going out. I've tried a different power supply. I've tried one DIMM rather than 4. I've re-seated the CPU (Intel Core i7-5930K).
I'm at a loss. Ideas?
