Hello, i just recently upgraded from a Cougar A-560 PSU to a Corsair Rm-750 in anticipation of crossfiring my currently single 7870 setup. My mobo is an Asus P8z77-vlk, I'm running two 4GB sticks of Gskill Sniper RAM, an I5-3570k (OC'd to 4.2 GHz), a Samsung 830 series SSD with Windows 7 and a Seagate Barracuda 2TB HDD for mass storage and non-vital programs (IE it holds everything my Steam addiction consumes ). So, after uninstalling the A560, I made all my connections with the RM-750 and went to boot up - only to be met with that dreaded infinite loop of getting past BIOS and then failing to boot Windows. I get my POST beep, lights flash as usual, everything - I can enter BIOS just fine, and here I can find all of my devices - drives, peripherals, RAM, everything, which means they are getting power and are detected. I hit the CMOS button, that came back fine, said memory was good. I can display via either integrated or board GPU. I can monitor stats in BIOS, and temps are fine across the board, so this isn't a CPU heatsink issue. My boot order is set to disk drive, then solid state (where OS is installed). If I select only SSD and then boot, still no luck. The PSU is obviously producing power. All my fans work fine, no odd noises or error beeps or LED's flashing out of the ordinary. I've checked all my connections and remade my SSD and CPU 8pin connections just to be sure. At one point, I had forgotten to feed my GPU its 6-pin power, but that is hooked up now and it displays fine. The first boot after I connected the GPU and got a display, it was at the same initial screen I get when I run the CMOS clear, except it had said some along the lines of "overclock failed". I haven't seen that on boots since, and my OC multiplier of x42 does still show up in the BIOS menus. I really don't know what is going on here. Any help is greatly appreciated.