Hi Lord Simpson,
Welcome to the forum.
Does your motherboard have the ability to switch BIOS? Does it have 2, just like the Maximus VIII Extreme? If yes, I would suggest, switching to the other one, removing all your RAM but 1 , and trying to boot your system. Hopefully it will POST correctly and not hang on the 00.
I would also suggest to test out your RAM sticks as well as your DIMM slots, and see which of them responds better and with which of them you get the less errors, given that you can move past the 00 Q code..
How did you use the flashback aftger you got the 00. Did you get into BIOS or is there an other way to update BIOS that I am not aware of?
When updating your BIOS I would suggest getting an empty USB stick, formatting it to FAT32 (actual format, not the quick one) downloading the BIOS drivers from the asus website and unzipping the *.cap file in the USB drive. After that remove and re-insert the USB on your computer to verity that the file can still be read, and then get into your BIOS and have it update.
When I updated my BIOS on my Maximus VIII Extreme, it would restart at least twice, and I would usually get a black screen saying "Bios is Updating" before it would boot successfully