Question CPU LED Stays On After Windows Installer BSOD — Ryzen 5 5600 on MSI B550-A PRO

[33P4BLO]

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!

 

[Colif]

if you get a BSOD during the installation process, its only going to be ram or processor or MB. Nothing else is in action until a later step in the install process

Try running memtest86 on each of your ram sticks, one stick at a time, up to 4 passes. Only error count you want is 0, any higher could be cause of the BSOD. Remove/replace ram sticks with errors. Memtest is created as a bootable USB so that you don’t need windows to run it

turn xmp off during the install and see if you can get past where you are.

Is ram on QVL of the motherboard? Did patriot test it with board?

Storage:not in

Its really hard to install windows if you don't have any storage in the PC - where is it meant to install it exactly?

I assume it was at one stage - Might need to wipe the ssd if its got a partial install of windows on it now - I can't tell since I don't know when it failed.

memory controller is on the CPU, could explain light maybe.

only real way to test a Ryzen CPU is to run Prime95 and see if it crashes. The results should show in a text file in the install folder for prime, from memory

instructions may be old, its a while since I used them:
Prime 95 Bootable - https://www.infopackets.com/news/10113/how-fix-bootable-prime95-stress-test-hardware
Prime 95 Instructions - https://appuals.com/how-to-run-a-cpu-stress-test-using-prime95/

 

[33P4BLO]

I ran Prime95 from Ultimate Boot CD. After about 10 minutes, the PC was still running at full speed, but the screen went black and didn’t come back – seems like it froze.

 

[Colif]

Does screen work again after a restart?

seems the results are stored in a temp folder in ram that only existed while PC was on
/tmp/torture-test/torture
So that doesn't really help.

What Power supply are you using?
shouldn't be over heating, its a brand new PC...
What case are you using? What cooler is on CPU?

https://www.tenforums.com/general-support/213014-screen-goes-black-after-prime95-processor-stressing-test.html

did you check ram? it shouldn't take long on 8gb sticks, longest part of test is actually when its doing nothing at all. It has one test that checks how well the ram maintains info, and its 15 minutes of nothing... I ran it on my sticks a few months back now. Pc only new itself.

 

[33P4BLO]

I tested ram with memtest+ - no errors
My PSU is Zalman MegaMax 500W.
My case is Krux Vako (polish brand)
Cooler is stock Wraith Stealth.
After restart pc works.

 

[Colif]

My PSU is Zalman MegaMax 500W.

@Lutfij do you know this model?

4 year old model.

zalman | PSU, Cases, CPU Coolers

www.zalman.com

I can't find a lot on it. It didn't impress anyone on here: https://www.techpowerup.com/286681/zalman-intros-megamax-v2-series-power-supplies

Oxc00021a

STATUS_SYSTEM_PROCESS_TERMINATED (this is an unusual BSOD. I seen plenty in last 10 years, this is rare) - is specifically caused by windows System files, so its an odd one to get on an install. These files shouldn't be corrupted on a clean install, since you say Installer isn't cause. Did you try another USB drive just in case?
If you get same error each time, it could be that windows is partially installed and the files are corrupted.
AS such, I would do this: (need the drive you installing onto in to do this)

Spoiler

Boot from installer

On screen after language choice, pick repair pc, not install

Pick troubleshoot

Pick advanced

Pick Command Prompt

Type diskpart and press enter

Type list disk and press enter

This will show the list of drives currently attached to PC, make note of the drive number of the drive you want to wipe

If Disk 1 is the drive you want to clear, type select 1) and press enter. A message will confirm it is selected

Warning: Diskpart Erase/Clean will permanently erase/destroy all data on the selected drive. Please be certain that you are erasing the correct disk.

Once you sure its right disk, type Clean and press enter

The Command Prompt window will display the message "DiskPart succeeded in cleaning the disk". Close out of the Command Prompt window by clicking the red X in the upper right hand corner.

That will leave you with a blank ssd, try install again.


PSU could cause that as everything relies on the PSU supplying power. It might explain why you got blank screen in Prime as it would have been using a lot of power at that point, and PC have been known to turn monitors off if they running low on power, its not seen as essential to PC.

Wait and see if Lutfij notices this, He might know brand better than I do. Or at least how good PSU is. Its a white label PSU with low efficiency.

 

[Lutfij]

do you know this model?
I do, but I have my doubts with that unit as it's labelled with a Zalman. I will always group Zalman, OCZ and Thermaltake's Litepower and Smart units in a corner of a dumpster. User created a similar thread on Tom'sHardware.

Hang on...lemme look further.

SPL's PSU Tier List

docs.google.com

+

PSU Tier List rev. 17.0g - Cultists Network

PSU Tier List will help you to choose the best PSU out of hundreds of models on the market. From budget to the highest end Power Supplies.

cultists.network

Yeap, trash!

 

[Colif]

I would get a different PSU, possibly from Corsair or another better known brand.
Seasonic are another good choice.
Don't want to go mad but it helps to have a good source of power or it can prematurely kill other parts

I haven't been on Tom's for a while.

 

[33P4BLO]

Guys I tried another power supply from a friend (600 or 650W) and it made no difference. The first thing that came to mind was the PSU, so I tried another one. But since that didn't help, I'm left with the processor, which I can return today. What do you suggest I do?

 

[Colif]

What is the new PSU?

If its easy enough, try swapping CPU.
I don't like not knowing the actual cause, swapping parts can get expensive if you not sure what cause is.

i would suggest something like this is a good PSU to start from:

RM Series™ RM650 — 650 Watt 80 PLUS Gold Fully Modular ATX Power Supply

CORSAIR RM Series Fully Modular Low-Noise Power Supplies provide quiet, reliable power with 80 PLUS Gold efficiency to a wide variety of PC builds.

www.corsair.com

what are the ram codes? it could just as easily be an incompatability there too. Just cause you didn't BSOD doesn't exactly count them out.