Too bad this is why you had to de-lurk. You have it down to the two possibilities - CPU or Motherboard. I had one like that -- Qcode 00 and CPU led -- that was caused by failure in the motherboard voltage regulators. No power to the CPU looks like a failed CPU to the BIOS. That time I had another CPU to try, so it worked out.
There are some things that have a slight chance to help: Try unseating and re-seating the CPU. When reseating, check that the cooler waterblock is firmly but not tightly fastened. Too much pressure from the cooler can move the CPU to where socket pins make no contact or only a little contact. The thought is that one such pin finally moved out of contact.
If it still won't post, I think the only clear way to distinguish between the two is to try another one of one or the other. Less conclusive, but maybe better in the long run is to contact tech support of Intel and Asus and ask both for warranty RMA.
I'm a long time lurker but this is my first post. I have had this system up and running for about a year now. Turned it on yesterday and got no post, no beeps only blank screen. Q code is 00 and the cpu led is solid red. I have tried most of the usual stuff: clear cmos, bios update, psu test, 1 stick of ram, no ram, different video card, on-board video, all drives unplugged, and so on...
I am fairly sure that it is my cpu but i just thought i'd throw this out here and see if there is anything i might not have tried ( i've scoured various forums and have tried most things). I do not have another cpu to try nor do I have another motherboard.
MB: M6 Formula bios 1505 (flashed to 1603 with usb method)
CPU: I5 4670k
COOLER: Corsair h100i cooler
GPU: MSi GTX760
RAM: Gskil F3-17000CL9Q-16GBZH
System Drive: 2 x Kingston Hyperx 3K raid 0
OS: win 7 x64
Any suggestions will be greatly appreciated. Thanks in advance!