New PC won't boot, lights blink & fans turn when connected with PSU

[Lisixz]

I've put all my parts together and turned the PSU on, but not the PC yet, the fans were spinning for a second but stopped working for a few seconds and then started again, same with the lights on the Motherboard and the GPU - they were just blinking. Then I've turned the pc on, the fans started running normally, but the lights were still blinking. I've already taken it out of the case and built it on a cardboard box, but it was the same. I don't know what to do...
My specs:
Intel I-7 6700k
Gigabyte Geforce GTX 970
Asus Z170 deluxe
Corsair H100i GTX CPU watercooler
Samsung SSD 850
Corsair Vengeance LPX 2x8 GB
bequiet pure power 630 W
Corsair Obsidian Series 750D case

 

[Lisixz]

Update: I called a friend of mine and he suspects that the Motherboard might be faulty, causing a short-circuit - what do you guys say?

 

[Cycloid Torus]

You might wish to check over this to be sure you didn't miss something... http://www.instructables.com/id/How-To-Assemble-A-Basic-Desktop-PC/#intro

Is there a troubleshooting section in the motherboard manual?

Double check all connections to the motherboard.

Did keyboard LEDs flash indicating BIOS recognition?
Did anything appear on display?
Did you get any 'beeps'? Any kind of pattern?
Motherboard LED flashing in a pattern?

 

[EliteCustard]

Your reset switch is probably in wrong. Try putting it in another way. Don't worry, nothing is broken

 

[captaincranky]

Try booting the PC with only one stick of memory. Try both sticks in turn, if only to rule out that as a reason for the PC not "POST-ing. (Power On Self Test).

An incorrectly installed heat sink fan assembly would also cause a premature shutdown.

Also, if one of the PSU voltages is off, improperly connected, or non existent, that could also cause those symptoms.

EDIT: IIRC, without a HDD (or SSD) connected to the system, the machine will boot directly to the BIOS. That might be worth a try as well.