I've finished my build today. Specs:
CPU: Intel Core i5-6600K
CPU Cooler: 212 Evo Cooler Master
Motherboard: Asus Z170 PRO GAMING ATX LGA1151 6
Memory: Corsair Vengeance LPX 8GB (2 x 4GB) DDR4-2666 Memory
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive
Video Card: Radeon R9 270x (Single)
Case: NZXT H440 (Black/Red) ATX Mid Tower Case
Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply
Case Fan: Corsair Air Series SP120 Quiet Edition 37.9 CFM 120mm Fan
Now, I'm not the best at building, but looking at it I don't see anything missing. I start it up, all the lights come on, the fans work. But nothing shows up on the screen. Also, after a while the computer reboots, and it's an ongoing cycle. Not sure if it reboots cause there's no operating system, but nothing on the screen. I've tried taking out the video card and use the motherboard, but same result.
I've taken out the Motherboard, left only the MB power cable in, the CPU power in, and the fan on top of CPU. Oh, and of course the panel cables so I can use the power button on the case. The MB lit up and everything, it booted and same thing happens, after a while it switches off and on again but no video output. Also, there was not a single beep. I'll attach a couple screenshots to show you guys.
That's all I left connected:
The CPU connected(I wasn't even sure where to connect this at first, it's two 4 pin connectors split up, so I just put two next to each other):