Question Pc suddenly shuts off and won’t turn back on???

[MEDICfromtf22]

I was in the process of upgrade my build and was in the middle of installing windows when my pc suddenly shut off, I tried powering it back on only to find out it wouldn’t post, I’ve tried all normal troubleshooting steps but nothing has worked.
Edit: I’ve tried an old psu I had on Hand and that produces the same problem

Specs
Amd ryzen 2600
Asrock steel legend b450m
Nvida RTX 3060
Thermal take tough power gf1 750w 80+ gold psuVideo below

 

[Nephern]

what did you try?