New PC Build wont display anything on monitor. Unless GPU is disconnected.

[jgchaos1]

When I turn on my new rig I just put together i get a "no signal detected" message from my monitor. The weird part is when I tested it, before putting it in the case and connecting it to the Storage and GPU, It actually displayed a get started message on screen. I've been trying to fix this problem for a while on my own with no success. Please Help I'm pretty new to this i'm fairly certain i plugged all the connectors in the right spots but i could have made a mistake. The power light turns on, the cpu and gpu fan both turn on, The Monitor also works with my Laptop, PS4, etc.
My build is:
-CPU: Intel Core i5-6500 3.2GHz Quad-Core Processor
-CPU Cooler: CRYORIG C7 40.5 CFM CPU Cooler
-Motherboard: ASRock Fatal1ty Z270 Gaming-ITX/ac Mini ITX LGA1151 Motherboard
-Memory: Crucial 16GB (2 x 8GB) DDR4-2133 Memory
-Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive
-Storage: Seagate FireCuda 1TB 2.5" 5400RPM Hybrid Internal Hard Drive
-Video Card: Sapphire Radeon RX 470 4GB Video Card
-Case: Fractal Design Node 202 HTPC Case w/450W Power Supply

The Monitor is BenQ GL2460 and I'm using HDMI
I've tried plugging the HDMI into both the GPU and the Motherboard with the same result.

When I remove the GPU from the system I get a Setup screen. I should be well within 450W which is what my PSU allows for.

 

[Paul NZ]

Did you put the standoffs in the case before you installed the mobo?

And you connected the 4/8 pin ATX12v, cpu fan and 24 pin?

 

[jgchaos1]

Did you put the standoffs in the case before you installed the mobo?

And you connected the 4/8 pin ATX12v, cpu fan and 24 pin?

I believe the Fractal Node 202 Case standoffs are built into the case. Yes I plugged in the 8pin and 24pin prior to putting it in the case and when i ran a quick test everything seemed to work (it displayed a get started message). Also now even with the PC not displaying anything all the fans are running.

 

[Paul NZ]

Could be the cpu cooler. Some can hit components or ram slots. And can / will cause probs

 

[jgchaos1]

Could be the cpu cooler. Some can hit components or ram slots. And can / will cause probs

I don't think so bc I had the CPU fan and ram installed when i ran my initial test. The Ram I'm using is also really thin so theirs no touching between the cooler and the ram.