Wow, Asus needs to work on the user manual for this mobo. No description of the rear I/O panel or mention of CMOS/BIOS reset. Had to look at pictures in website to establish where the reset jumper/button is.
Anyways, according the Q-Code table, system is ready to boot. Try resetting the BIOS with the button on the top right of rear I/O panel, 'Clear CMOS'. If you can now get into BIOS, set it to default (F5), save and restart. If PC now boots, it was a BIOS setting. If it still doesnt, try the following:
1) Unplug all unnecessary USB devices. Have only keyboard and mouse plugged in. If it now boots, faulty USB port or device.
2) Ensure the AIO cooler is plugged into proper headers. To eliminate this from the problem, plug AIO into PSU cable instead of mobo header and see if problem persists.
3) Try a different HDMI or Displayport cable.
4) Ensure all PSU power plugs are fully seated.
5) Try re-seating GPU and Memory.
6) Ensure CPU is seated properly in socket.
I am no expert, but with what you described, this is what I would start with.