Question My computer lights up but won't turn on

[Astralstars]

I just finished building my new computer,and no matter what i do it refuses to boot up. I tried using the power button on the motherboard, but it still doesn't work. the rgb lights that are installed on it work but everything else doesn't.

 

[Lutfij]

Welcome to the forums, newcomer!

Please list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:

 

[Astralstars]

CPU: ryzen 5 5600x
Motherboard: asus rog crosshair Vlll hero (wi-fi)
Ram: g skil trident z neo 16 gb (8 gb x2)
SSD/HDD:samsung 870 evo sata lll SSD 1TB
GPU:gtx 1050 ti
PSU:evga 400w
Chassis:corsair 400d airflow

 

[drivinfast247]

Did you connect the CPU power pin to top right of motherboard? RAM installed in slots a2-b2?

 

[Astralstars]

Yes i made sure that both the cpu pin and ram were plugged in.

 

[drivinfast247]

Are all these parts new?

 

[Astralstars]

yes all of them are brand new.