Question PC won't post. Replace the motherboard?

Jul 15, 2020
link to my previous post

After my previous post I took the entire PC apart and put it back together, after which it DID POST for only a few minutes during which I was able to flash the BIOS successfully and run the computer normally. However, after noticing my headphones weren't being recognized, I replugged the audio pins and now it's reverted back to no post.
Also, it did not post the first time after being reassembled. There were several attempts where the pc would post for a few seconds before shutting down. Only after multiple attempts was I able to post and flash the BIOS.
Am I right to assume this is a motherboard issue?
  • I've read forums where people had similar issues with the MSI Tomahawk B450.
  • I attempted to flash the BIOS once everything was off the motherboard. But the flash LED would not indicate that it was working, nor did it flash at all when the button was pressed.
  • There's also the fact that since day 1 my motherboard LEDs and the CPU/system fans would continue to run after shut down or when the PSU was switched on at all.
  • I also tried different configurations with my RAM slots and it didn't seem to make a difference.
I think my best bet is to replace the motherboard with a different one. I'd really appreciate some feedback tho :)
TL;DR - My PC won't post and after troubleshooting I think I should buy a new motherboard.