And now from the last 3 days the system doesn't boot. When I power on the computer, all fans start spinning but keyboard and mouse LEDs don't light up. Pressing CTRL+ALT+DEL doesn't reboot system neither does pressing the power button for few seconds.

I suspect that motherboard has gone kaput and isn't completing or even starting the boot process, which is why keyboard and mouse aren't getting any signal or power from motherboard or why restart or power down functionality is working.

Before the system stopped booting, I was trying to solve the machine check exception error by updating BIOS, updating chipset drivers, changing BIOS settings etc. But now I'm thinking none of it could've helped because the board itself was deteriorating.

Also during that time, I would randomly get display glitches (pic below) which could only be solved by restarting the machine so I was suspecting it might be GPU that was causing the problems.

Sometimes it would show chessboard like pattern. I guess this was also because of some issue with mobo-GPU connection?

Anyway before changing the board is there anything else I can try? Changing it is a pain so I'm trying to avoid that. 😂

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[–] [email protected] 3 points 2 months ago* (last edited 2 months ago) (1 children)

There's no onboard video for this setup* but I'll try to boot without GPU.

*Only Ryzen CPU with G suffix have integrated graphics. Plus, my CPU is Zen 2 which didn't have integrated graphics at all.

In short, during POST of the BIOS it attempts an init to the display, fails and then stops attempting the boot sequence. It, the video card, is just as important during init as the motherboard registers, RAM and CPU all starting.

I wasn't aware of this. I assumed display check would be last considering there can be systems without display.

Let me check if I get NUM LOCK and CAPS LOCK LEDs after removing GPU.

[–] [email protected] 2 points 2 months ago

While I call it init, many will assume I am referring to the boot init, but I am actually referring to the bios initialization (init).

That said, most BIOS inits go in this order:

Power Detection check. If enough power, proceed.
CPU program link, CPU calls the BIOS to basically wake up and run the bios program.
Ram Detection check. If RAM is present, the BIOS will use about 64k to load from ROM to RAM (called the bios reserve area) that then does the next steps.
Hardware Detection check. Identifiers of the hardware are detected, enumerated, configured and initialized.
Boot Sequence is initialized whereby the BIOS does a handoff to the bootloader.

It's during the hardware detection phase when the display is initialized by the gpu and you often see it displaying the bios version, then counting RAM. If the gpu is working BUT the display out isn't, it'll actually continue to boot 100% of the time (it doesn't care). If the gpu hardware itself doesn't respond correctly to the BIOS request however, it sends the hardware detection of the BIOS into a loop or shuts the system down, never getting to the final step: boot sequence.

Depending on the bios type, it may or may not show numlock. I've also seen it act differently on UEFI enabled systems than when it's set to classic bios. So, it just depends.

Regardless, see if you can source another pcie gpu for testing this. It only takes a minute and tbh, it doesn't hurt to have a cheap used pcie vid card in your pc tools for such things.

Good luck!