I thought this problem had gone away, I didn't have any problems in the past week, but it reappeared this evening.It looked like the PC didn't actually boot properly into Windows, because the keyboard/mouse lights were off and the PC turned off imediately when I hit the power on/off button. I had to turn off and hard reset the PC numerous before I saw the BIOS screen and Windows loaded.
Once Windows loads, I don't see anything wrong with my system. Everything works properly, I can play games, run stress tests, no problems at all. But once in a while there's something odd going that stops the system from booting properly.
Does anyone have any idea what's going on? It's a brand new system: GA-X99P-SLI (F22 BIOS) with Broadwell-E Core i7 6900K CPU + EVGA GTX 1080 card + Samsung M2 SSD Boot drive.