Postfix issues? Mobo/RAM light on

[Aarinesque]

Hey

My boyfriend and I are currently having some issues with a PC we are building. We can't access the bios, blank screen, the cpu light on the motherboard is lit up when the ram is in but if we take the ram out then the ram light on the motherboard is lit up instead.
We've already checked all the cables and triple checked the cpu to ensure it was in correctly though this is our first time building with AMD.
We've tried everything we can think off and would really appreciate any help.

Specs:
Motherboard MSI B450 Tomahawk
PSU Corsair CX 450M
CPU AMD Ryzen 3 2200G
RAM Corsair 16 GB 2400 MHz
Graphics card Asus strix GTX 960

 

[Dark Lord of Tech]

Why such slow memory for Ryzen? Should be at least 3000mhz.

 

[Aarinesque]

We have tried a 3000mhz one as well that are meant for another pc. But we still get the same problem.