Pc not starting up

[Yalloin]

So here i am building my second pc, and carefully checked everything so it should have been fine. But when i push the power button. My motherboard flashes 1 second and i hear a click from my power supply. So i jump started it with the Paper clip test and the fans turned on and spinned.

But when i connect everything back to my pc it gives the click again coming from my power supply. I have no idea what the problem could be now. ( Also tried to start it without the gpu, same problem )

 

Thanks

 

Build : 

motherboard : z390 aorus ultra

cpu : intel core i5 9600k

psu : gigabyte aorus p750w 80+gold

Ram : Corsair 16 GB DDR4-2666

gpu : GIGABYTE AORUS GeForce RTX 2070 8G 

hdd : Seagate IronWolf, 2 TB 

SSD : Samsung 860 EVO 500GB

cooling : Cooler Master MasterLiquid ML240R RGB

 

 

[Jumballi]

Step 1: Reseat everything
Step 2: Run system without gpu, 9600k has integrated graphics just for this reason. Run with one stick of ram in the other slots.