The ASUS Sabertooth Z77 motherboard comes with a USB BIOS Flashback which allows you to load the BIOS on to a USB stick and then reboot and reload the BIOS onto the board. Here's the ASUS product page where you can download the latest BIOS for your motherboard and reflash it. Read the Manual too as you may not have your DIMMS in the right spots because if you have dual channel RAM some boards need the DIMMS in specific channels. Here's a link to the ASUS Download Support pagehttp://www.asus.com/Motherboard/SABERTOOTH_Z77/#support_Download
Thanks for the response, unfortunately the problem still persists. I double checked my RAM is installed in the correct place and it is, and that didn't solve the problem either. Although now it restarts pretty much immediately after pressing the power button.
If you had to manually set the RAM to run at DDR3-1866 then that tells me that it's of the variety that doesn't natively run at 1866 and has to use the XMP profiles to do so. I've found that this type of memory to be some of the more problematic, frankly you gain zero benefit over running at 1600 btw, and simply isn't stable at 1866. You should be able to get out of the boot loop by clearing the RTC RAM. It's a jumper labeled CLRTC on your board. Clear that and report back with what happened.