Question Got only one POST after replacing power supply, will wake monitor

[ewrc]

Components
PRIME B-450 PLUS (note, PCIE slot 'clip' fell out)
R7 3700x
RX 5700 XT
Coolermaster MWE 650w

I replaced my powersupply and FINALLY got a post after having post issues that started randomly, the GPU fans wouldn't turn on and would "quiver" once the computer turned off.

So I replaced the PSU because I guessed that it was a power delivery issue and well, I had no cpu cooler on, so I got a "CPU fan header" post, but, at least I got an output. I have since tried reseating everything (except cpu lol i guess that's next step) and tried to get the same post error by unplugging the cpu cooler fan, but alas. When I turn the computer on it will wake up the monitor but I'll get no post... so I'm not sure what to do now...

 

[ewrc]

When reseating the CPU I noticed corrosion on 2 or 3 pins, i squirted it with isopropyl but it didn't seem to improve, these components are at oldest 18 months so i'm not sure what these means

 

[ewrc]

swapping out GPU provides same issue - wakes monitor but no output. new motherboard this time.