While I have it on good conscience that this is due to the Corsair H80i, here it goes.
I recently installed a Corsair H80i. When attempting to boot, I'm get a long string of q codes that were initially ending with 20 before shutting off, then looping back on to do the same thing. I checked all of my connections and now it will hit 56 or 4F before shutting off. Earlier it was 20 and 62. It hasn't reached BIOS once. The cooler's fans are turning on just fine, but it's hard to tell if it's the cooler or what would be wrong with it.
I checked to see if the new heatsink was on too tight (just loosened a little), but that had no effect. Removing power from the graphics card did not work, but I didn't remove it entirely. New thermal paste was put in when the new heatsink was put on.
Update: Removed all connections to cooler and issue persisted.
I noticed that the slow mode switch was set on, so I turned it off. The PC booted to a screen telling me to hit F1 to go to the BIOS for something about a profile (Bios revision 0701 "please enter setup to recover bios settings"). I went to the bios and had the PC restart, but then it got into a boot loop again.