I too am having the same issue. The red LED comes on when the machine is powered down, and the next boot will give the "Catastrophic Power Event" message. Hitting a key at that point will allow it to boot successfully into Windows 8; however, the LAN1 port will not connect to the network even though the lights are on. (Moving the ethernet cable to LAN2 allows Windows to connect, but moving it back to LAN1 doesn't work.) A simple restart from Windows will work fine, without any catastrophic power message, and Windows can connect to the network on LAN1 as well. In fact, everything seems to work perfectly until I do a complete shutdown, at which point the red LED comes back on and we're back to square one.
Likewise, I can't update the BIOS to 0344 (it's currently on 0336). Attempting to do so just results in a shutdown with the red LED on, after which it takes 3 presses of the power button to get it to restart. The first two tries with the power button will just make the lights flash and fans spin for a second or so, and then it shuts down again. The third time will boot successfully, but with the catastrophic power event message, and the BIOS not updated.
My power supply is also a Corsair AX860i, which was recently added to the Intel approved list. I also have a Samsung 256GB SSD and two WD 2TB HDDs, similar to the original poster.
A solution to this problem (or at least a decent explanation) would be greatly appreciated!