Question PC wont post but fans spin for a second on upgraded build.

[Robster97]

Hi!
I recently upgraded my PC's motherboard, CPU and RAM and it wont post.
The CPU, case and GPU fans spin briefly and then it dies.
I have rebuilt it 4 times by now and no progress.
Fairly certain that the cables are working and in the correct place.
You reckon its a hardware problem or what should be my next step troubleshooting this?

System:
Ryzen AM4 5600G
ASUS A520M
2x8GB Vengance RGB pro
620 W psu
GTX 970

 

[Zerk2012]

Probably need a BIOS update to use that processor.

 

[Robster97]

Probably need a BIOS update to use that processor.

Thanks for the Quick reply!
Will try this

 

[Robster97]

Probably need a BIOS update to use that processor.

I assume i need a compatible CPU in order to do that right.. Because my old one is an intel I7 from 2006 or something and i doubt that one will work?