To start this is originally a 7700x, msi b650-p wifi, 32gb g skill flare 6000 build from 2023 with an MSI 850w PSU, ran with no issues until about a month ago.
I started having issues with intermittent booting, I would boot the PC and it would sit in an idle state with CPU/dram lights both on indefinitely, and I could "solve" this by repeatedly force shutting down and rebooting, eventually it would boot, and have no issues at all until I shut it down, with absolutely no stability issues until it was shut down again.
I took it to microcenter since I had no idea, and they did a horrible job troubleshooting, just telling me to buy a whole new mobo+CPU+ram combo saying all 3 components were faulty.
I bought a combo to test myself, identical CPU/ram, and a new mobo. Every combination of this setup and my old components booted 10+ times in a row, other than my motherboard.
So at this point it seemed to be clear the motherboard was bad, since I could boot just fine with my old CPU/RAM.
I returned the bundle since I only needed a mobo.
I then bought a refurb motherboard, which would sometimes boot, and sometimes the only thing that would turn on is the GPU lights, case fans, CPU fans, lights all stayed off. This board had no debug lights so I was not sure what the reported issue was. I figured this was just yet another faulty board, since the other bundle one had no issues.
So yet again, I returned that board and got a new Aorus b650e elite ax board. This then proceeded to boot first try no issues, so I figured everything was good and went on with my day.
Now it's the next day, I booted the PC, and it got stuck with a dram light on for 30 minutes, which I figured was well beyond the ram training time, especially having booted yesterday.
I shut it down, rebooted, then it got stuck in a state flashing between CPU/DRAM lights indefinitely. I took one ram stick out to try to debug, it booted fine. I put the stick back in, same flashing back and forth boot issue. Took that ram back out, CPU/dram still flashing...
At this point I am just baffled as to what the issue could be. I've never heard of faulty cpus/ram working flawlessly once already booted, but I genuinely don't know what else could be happening here.
I'm currently attempting to reseat everything including power cables, ram, CPU cooler, but this is beyond me and would appreciate any help. Everything I search on these problems are from people first booting, not something that was already working and just stopped overnight.