New PC won't turn on -- faulty PSU, CPU, MB?

After putting everything together (all brand new parts, arrived today), the computer won't boot. No lights, no PSU fan spinning. No POST. Nothing at all. My standoffs are all where they are supposed to be (although some seem to be more flush with the case than others).

Specs:
Cooler Master Elite 430 - Mid Tower Computer Case with All-Black Interior (RC-430-KWN1)
Intel Pentium Dual-Core Processor G860 3.0 GHz 3 MB Cache LGA 1155 - BX80623G860
Samsung 840 Series 2.5 inch 120GB SATA III internal Solid State Drive (SSD) MZ-7TD120BW
Cooler Master eXtreme Power Plus 500w Power Supply (RS500-PCARD3-US)
EVGA GeForce GTX 650 1024MB GDDR5 DVI mHDMI Graphics Card 01G-P4-2650-KR
AS Rock PRO4-M LGA1155 Intel H77 Quad CrossFireX SATA3 USB3.0 A V GbE MATX Motherboard H77
Patriot Gamer 2 Series Division 2 Edition DDR3 8 GB PC3-12800 1600MHz 9-9-9-24 Memory Modules PGD38G1600ELK

I breadboxed it and still nothing.
After that, I unplugged everything from the PSU and shorted the green and black with a paperclip. When I do that, the PSU fan spins.
I plugged the PSU back into the motherboard and tried shorting the POWER SWITCH pins in case it was a problem with my case. Nothing.
I then plugged my motherboard into a spare computer's PSU. Again nothing.


I just ordered a replacement motherboard, but I want to make sure that this isn't also/instead a CPU problem. Thoughts? Even though the new mobo is coming, I'll take any troubleshooting suggestions. Would love to get everything up and running before the replacement arrives on Thursday. Side note, my case has two different sets of screws that are really difficult to tell one from the other. If the screws fit in the standoffs, they're most likely not going to short the board, right?