I came home to the computer being off (I had left it on), and now when I try to power it on, the fans spin on for a second and then turn off, and the whole system restarts that loop, and will do it continuously until I cut the power. The error code on the motherboard is jumbled during the restart, but does start on 19. If I remove all the RAM sticks, the board starts up, no post or anything, but does power up and sit there with error code 53. I've tried all the RAM sticks in different RAM slots, to no avail. Is it possible that all 4 of my RAM sticks died simultaneously or something?
There have been a lot of DIMM slot issues with the X79, and I seriously doubt you have 4 out of 4 bad sticks of RAM.
Interesting, I looked at your manual, but other than A1, B1, C1, D1 it doesn't state how to install 1, 2, or 3 sticks of RAM. It does state left to right with 5-8 sticks.
Below is the ASUS's version of 1-8 sticks of RAM, and it can't hurt to try (1) stick as listed below. The best I can garner from your manual is DDR3_A1 slot. However, since ASUS essentially owns ASRock (Pegatron Corp) it's worth a shot. And no it won't help/hurt for the RAM to be in an incorrect DIMM slot.
I would first perform a Clear CMOS (don't if you have a RAID array), unplug 5 minutes (PSU discharging) then press and hold the 'Clr CMOS' button for 10 seconds.