Question PC died, EZ Debug VGA light on, tried a bunch of things, no clue what's wrong

[thenevernow]

Hi everyone, here's my sad story. There was a storm the other day and it did some damage to my PC, but 4 days and a lot of frustration later, I still can't figure out what's wrong.

Setup:
Motherboard: MSI MPG B550 Gaming Plus
CPU: AMD Ryzen 5 5600x
GPU: Sapphire Radeon 7900 GRE
RAM: 32GB (4x8GB) KINGSTON FURY Renegade DDR4-3200
PSU: be quiet! Pure Power 12 M 750 Watt (replaced with a Corsair Rm850X, see below)
Storage: WD Black SSD SN770 M.2 2280
Case (just in... case): Fractal Design Pop Silent Black Solid

The storm hit, the computer failed and turned off. I understand the damage could be limited to a cable or the whole thing could be fried, I accept that, stay with me.
The storm is over, the computer won't turn back on, I open it up and the EZ Debug light is on (solid white). Oh no, my GPU is dead! But I have an older GPU around, so before succumbing to despair I swap them and nothing changes. Ok, so maybe it's not the CPU. Other parts from my other PC are not swappable (too old and Intel-based), so I need fresh components.

First, I got a new MB, same as the old one. Exact same behaviour. Then the CPU (same one), still no luck. I thought "Ok, it's the PSU" and got a new one (different from the old one, see Setup above). Nothing.

Things I HAVEN'T tried yet:
- replace the RAM. I did however swap around the 4 modules I have. I can't be sure but they don't seem to be the problem. The EZ Debug RAM light never turns on when at least one module is installed.
- remove the MB from the case
- sacrifices to the Great Old Ones

Things I HAVE tried:
- verifying that the monitor the PC is connected to works fine
- replacing the HDMI cable
- using a DVI cable (with my older GPU) instead of HDMI
- replacing the power cable
- using a different wall power outlet
- booting without a monitor attached and with one
- removing the M.2 SSD or leaving it in place
- removing all MB-case connectors (fans, USB, audio). I even tested with no CPU fan connected but briefly, for obvious reasons
- checked that my older GPU works fine - it does. I know my CPU doesn't do video so I need an actual GPU in place. Put it back in the old system, all good
- tried the other PCI-E slot for the GPU
- cleared the CMOS (but probably irrelevant as I am now using a brand new MB)
- read all relevant conversation about EZ debug I could find here and elsewhere (nothing actually helpful, what I gathered is that the VGA light is supposed to also cover PCI-E and M.2, but is seems that people had it on and the issue was with the CPU or the MB itself or something else)

I hope I didn't forget anything. I know I still have a couple of things to try (replacing the RAM, mainly), but if anyone has any clue what's going on and what I should do, I'd be infinitely thankful.

Also, a couple of specific questions:

- is my PC (my MB, really) boot (to a BIOS error screen, at least) without a storage device attached? I'm assuming yes, but I could always be wrong
- same question, no monitor connected. Same assumption as above

Thanks in advance! 🙏

 

[Lutfij]

Welcome to the forums, newcomer!

You might want to see if you can perform a BIOS flash, using the BIOS Flash button on the rear of your motherboard, in tandem with the info given in your motherboard manual;
https://download.msi.com/archive/mnu_exe/mb/MPGB550GAMINGPLUS_EN.pdf
Page 51. See if that helps revive your system.

If you were tethered to the internet using your Ethernet port, then it's possible your board and everything connected to it was fried. You will need to cross-reference/swap/drop all your components onto known working parts and vice versa to rule out what parts conked out. I'm assuming everything and over time you'll see more and more parts fail or exhibit odd behaviors. You should consider sourcing(borrow, not buy) parts to help you in your troubleshooting process.