Issue with CPU LED remaining illuminated following Windows Installer crash screen — Ryzen 5 5600 on MSI B550-A PRO
Issue with CPU LED remaining illuminated following Windows Installer crash screen — Ryzen 5 5600 on MSI B550-A PRO
Hello everyone,
I’m experiencing a persistent issue with my newly built PC:
CPU: AMD Ryzen 5 5600
Motherboard: MSI B550-A PRO (BIOS updated via Flashback to latest version)
RAM: 2x8GB Patriot Viper 3600MHz cl17 (running at default 2133MHz, no XMP enabled)
Storage:not in
GPU: Gigabyte RX 6600 XT Gaming OC
Problem description:
The system boots up normally, CPU LED lights up briefly during POST, then VGA and Boot LEDs go off, and the PC proceeds to Windows Installer. During installation or after a Blue Screen of Death (BSOD) error in Windows Installer, the PC restarts but gets stuck with the CPU debug LED constantly lit and only the CPU fan spinning. The BSOD I get is Oxc00021a. No display output is received after this point, and the system does not proceed with POST again.
Removing RAM causes the RAM LED to light up as expected, confirming the motherboard detects missing RAM. BIOS correctly detects CPU with proper core count and frequency. PSU and cables verified, no bent CPU pins, thermal paste applied properly.
What we know:
BIOS is definitely updated correctly.
The CPU is detected fine by BIOS and POST completes initially, so it’s likely not dead but may have issues during warm reboot or initialization phase.
RAM is recognized but runs at a default low frequency with voltage around 1.19V, which might be borderline unstable for this kit.
The problem occurs reliably after a Windows installer BSOD or system restart.
Removing GPU shifts the LED to VGA, so GPU is detected and seems fine.
Both RAM sticks inserted individually into port A2 do not change anything.
Another motherboard didn't fix it either
Likely cause:
The CPU debug LED staying lit after restart strongly suggests a failure during POST caused by memory initialization instability or CPU initialization failure on warm reboot.
RAM voltage possibly too low for stable operation without XMP, but voltage change hasn’t been tried yet.
Could also be a rare CPU fault causing failure after initial cold boot but stable BIOS POST.
Windows installer and USB drive is definitely not a problem.
Any advice or similar experiences would be greatly appreciated!
Thanks!
Welcome to the forums, newcomer!
my newly built PC:
CPU: AMD Ryzen 5 5600
Motherboard: MSI B550-A PRO (BIOS updated via Flashback to latest version)
RAM: 2x8GB Patriot Viper 3600MHz cl17 (running at default 2133MHz, no XMP enabled)
Storage:not in
GPU: Gigabyte RX 6600 XT Gaming OC
Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. Please state the BIOS version for your motherboard at this moment of time instead of stating
latest
.
Where did you source the installer for the OS?
The problem occurs reliably after a Windows installer BSOD or system restart.
You state having no storage in the system, then what are you trying to install the OS onto?
CPU: AMD Ryzen 5 5600
CPU cooler: Wraith Stealth
Motherboard: MSI B550-A PRO
Memory: 2x8GB PATRIOT Viper Steel 3600mhz cl17
Storage: Lexar NM790 1tb
GPU: Gigabyte RX 6600 XT GAMING OC
Power Supply: Zalman MegaMax 500W v2
Chassis: Krux Vako
Operating System: Windows 11 Pro
Display: KTC H24F8
PSU details: Model ZM500-TXII, ATXV12 Ver2.31
Installed two weeks ago.
BIOS version 7C56vAJ from 2025-05-12.
Used media creation tool from Microsoft; official ISO and Rufus failed. Also tested various USB drives and motherboard ports without success.
Previous experience: Same issue with Gigabyte B550 Aorus Elite, changed motherboard but no improvement. Did not install SSD for testing purposes, only checking if the installer would run properly.
Model ZM500-TXII
https://docs.google.com/spreadsheet...pZ...=931697732
Category E...that is a terrible unit.
Edit;
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I also used a different power supply from a friend (600 or 650W) but it didn't make any change.
I attempted another power supply from a friend (600 or 650W) but it didn't make any change. For clarity, could you share the brand and model of your PSU? Also, how old was his unit and what did it previously provide power for? To clarify, a PSU can only be one wattage, either 600W or 650, so which one is correct?
Honestly, it doesn't address the issue. Wattage isn't the sole factor when evaluating a power supply unit. A PSU that's been used and aged will deliver less power than it did originally. If you received the PSU from someone else, you should have checked the label on its sides.