So you tried removing your 770 and posting with only the onboard 6700k iGPU?
Try posting with only one stick of memory installed and with no USB devices attached.
If you can verify no bent or broken socket pins
and if none of the above works, the PSU would be next on my radar screen.
Do you have another unit that you can test in your system?
Have you tried assembling outside of the case to rule a possible electrical short?
When your system halts with the 35 QCODE, do any of the QLEDs beside the 24 pin power connector remain lit?
Correct. The QLED will remain lit if a problem was present.
Clear your CMOS for me. Then insert a single module in the DIMM_B2 slot. Power on your system. If it halts, press the MemOK! button on the motherboard. See if your system is able to post.
Also do you have the 8 pin power cable connected to the motherboard header?
Please remove everything from your case and put the motherboard on top of the cardboard box that it came in. Use only the bare minimum.