Replaced CPU and GPU now PC wont post!!!

[Rock Steady]

PC specs:

Ryzen 5 2600X

B450I gaming motherboard

Vega 64

x2 8GB Corsair Vengence Pro 

Corsair SF600 psu 

NZXT h200i itx case

x3 ssd

 

I bought a new GPU( RTX 2070) and CPU( Ryzen 9 3900X) and installed them in my system. But when I went to boot up my system all I got was a flash of lights then the system shuts down(shown in the video attached). I tested all the components and made sure it wasn't the RAM, RAM slots, GPU, or CPU and now Im thinking its the motherboard. I put my the old CPU and GPU back in and tryed to boot but I get the same issue. I don't think I shorted the system, I made sure the system was unplugged while I was installing the components and that the psu switch was off until I wanted to boot the system. I also tryed to clear the CMOS but Im still getting the same problem. Anyone got any ideas on how to fix it?

 

P.S I attached a video to show what the system does when Itry to boot the computer. 

[Rock Steady]

I tried to boot with my old CPU but the system wont post even though I put the old parts back in.