Third build problems... Not booting

Hey everyone!

Okay, so I recently decided to upgrade my computer (well... I actually had to replace almost everything so it's pretty much brand new save the hard drives and powersupply).

Components:
Motherboard - MSI Z270 GAming Bro Carbon
RAM - Avexir Core DDR4 - 2400
CPU - Intel i5-6600k
CPU Cooler - Cool Master Hyper 212 EVO (thing is a monster)
Case (if you care to know) - Corsair 750D Airflow Edition
Video Card - Asus GeForce GTX 1070
PSU - Corsair CS Series Module CS750M - 750 watt (80 PLUS Gold certified)

Now, as this is my third build, I am familiar with the building process. Thermal paste was applied lightly, motherboard was mounted appropriately, all components are compatible.

What's happening:
When I power on my new PC, everything lights up and spins. You can hear the hard drives working, the LEDs in everything light up (GPU/Motherboard/Ram). There's no speaker on my motherboard so I wouldn't be able to hear beeps even if there were any. I noticed that my keyboard, mouse, and headset do not light up (I'm a sucker for RBG lighting).

There are "EZ debug" LED lights on the motherboard itself. Initially upon booting, the CPU light flashes, the RAM light stays lit for a little longer and then both go out. To check to see if this meant anything, I proceeded to remove the plug from the PSU to the CPU which caused the CPU light to remain stagnant the entire time it was booted, it also shut off all the of the LED effects on my motherboard to show that it was grumpy. I returned the plug and repeated the process with the RAM which had the same effect minus the fact that the RAM light was now lit

• • Just called MSI to confirm that the initial lights are just the motherboard receiving power**

Things I know for certain/trouble shooting steps I've taken:
My PSU is fine. I currently have it in my original computer. I'm also using the monitor, mouse, and keyboard that weren't responding initially in the new build. These things are perfectly fine.

I've removed the graphics card and tested the monitor through the onboard port (even though it was a futile attempt as the other peripherals aren't reacting). Still nothing.

I removed all ram except for one, moved it to several ports, and then switched that ram for the other stick and repeated the process. Still nothing.

I checked the CPU for any thermal paste problems and there was nothing but an itty bitty line along the side of the metallic part of the CPU. I cleaned that off with 70% isopropyl (pure... doesn't have additives) and checked the pins on the motherboard. All clear there. Nothing was bent, nothing looked out of the ordinary at all.

I also reset the CMOS using a jumper as well as resetting the battery.

Sadly, I cannot check the other components (RAM and CPU) because my current (working) computer is several years old and won't support any of my upgrades (hence the new motherboard).

Yes, I was grounded during assembly. Yes, I ensured that I didn't touch anything I wasn't supposed to. I also checked to make sure the motherboard touching the case in any way causing it to short. I've tested disconnecting the fans, I've carefully cleaned ports, I've reset the ATX and the CPU power cables. I've pretty much tried everything I possibly can at this point.

Thoughts:

I am unsure if it is the motherboard or the CPU. The debug light isn't saying that the CPU is failing or being undetected. It also doesn't say the same for the RAM unless either are completely disconnected.

I called a professional in my area to see if they'd test the components to try to isolate the issue. After about 15 minutes of explaining everything, he told me it's more than likely the motherboard and I should just go ahead with a replacement. The MSI guy said the same thing after a similar discussion.

I just wanted to get a third opinion as this whole replacement process can take an eternity.