Details if you don't mind, please. What broke?
Here are the details:
At the beginning of may I built a new PC: B660M-ITX from ASRock, i3-12100F, 2x4 GB OF RAM, RX 6400, 250 GB SSD.
At the beginning of June I started experiencing glitches an instability. I was watching a YT video, and suddenly computer black screened, the sound glitched, and after quite a few moments, computer naturally rebooted, and everything was fine. Next two days - everything was fine. Third day: again, same story, computer black screened, just after boot, without doing on it anything, after few moments it naturally rebooted, and worked perfectly again.
Until the same day, later...
During playing a game: same story: black screen, glitched sound, and attempt to reboot, but this time - no POST.
So I did the usual things:
1) cleared CMOS, by disconnecting the battery, and doing full power cycle. No POST.
2) single channel RAM, tried every configuration of memory kits: single channel, swapping the memory banks, swapping Memory places, etc. Every, possible configuration. No POST.
3) Took out the SSD - no POST, with or without the SSD.
4) another GPU - no POST, my GPU works in another machine.
5) The problem was narrowed down to CPU or Motherboard problem.
Yesterday I got CPU replacement from Intel. Still no post, but this time, something is different.
The fans spin, like previously, the LEDs flash, like they did previously, the keyboard and mouse light up, after quite some time, and after the USB is initialized - there are 5 beeps from system speaker.
Previously - not even USB would initialize.
Motherboard or the CPU. Since the CPU is brand new - its the motherboard.