PC Won’t Boot Sometimes: Debug LED Clues - Seeking Advice

Ardentio · April 18

My Problem Overview:

My PC occasionally won’t boot (no POST). This only happens a few times—not every time—and when it does boot, it works perfectly fine. This inconsistency confuses me as to why the problem occurs.

I have posted about this issue before but unfortunately received no replies. At that time, I tried all the No POST troubleshooting guides from the README, but none completely fixed my PC. However, I want to highlight some clues about why my PC experiences no POST in hopes that someone can help me. Any insight would be much appreciated.

My PC Specifications:

CPU: AMD Ryzen 3600
Motherboard: AsRock B550M Pro4
GPU: XFX Radeon RX 7700-XT
PSU: Enermax Revolution D.F.12 850W 80+ Gold
Memory: Klevv 16GB RAM, dual channel, 3600MHz
Storage:
- NVMe M.2 256 GB (Windows only)
- WDC SSD 1TB (Game storage)
- WD Blue HDD (Data storage)

The Problem:

My PC experiences no POST occasionally—only a few times—but most of the time it boots without any issues. I haven’t figured out why this happens yet.

After updating my BIOS to version 3.40, I noticed fewer no POST incidents compared to version 3.61 which caused more frequent failures. So initially, I thought the BIOS version might be causing this problem.

However, recently it started happening again; just this week alone I've experienced four consecutive no POST events.

To get my PC to turn on after a no POST event:

Sometimes restarting using the front panel button works once after several failed attempts (rarely help).
Turning off and then turning on again via front panel helps boot two or three times (sometimes help).
Power cycling has a higher success rate but still isn’t guaranteed; sometimes I need to power cycle twice before it boots successfully.

Some Clues That Might Help:

Debug LED Behavior

My motherboard has Debug LEDs for Boot, VGA, DRAM, and CPU status indicators.

When my PC boots successfully: The last two LEDs lit are BOOT followed by VGA.
- The BOOT LED stays on until the motherboard logo appears; then both BOOT and VGA LEDs turn off together.
When experiencing no POST:
- The BOOT LED turns on then off,
- Followed by VGA LED turning on,
- Then BOOT LED turns back on again, resulting in failure to boot.

(I have attached a video showing this debug LED sequence during a no POST event.)

SSD M.2 NVMe Health

Using OCCT software to check health status of my NVMe drive containing Windows shows around 94% health. Despite not being at full health:

It still functions normally,
Command Prompt checks report its status as OK.

(Screenshot from OCCT is attached.)

Random GPU Low Performance While Gaming

Not sure if it's hardware or game-related bug:

In Monster Hunter Wilds — runs fine with normal GPU performance.
In Tavern Master — experienced very low FPS; GPU usage dropped drastically (~10%) with power consumption around 60–75W instead of usual ~70–80% usage at ~150–200W power draw during normal operation.

My Hypotheses About What Might Be Causing This:

Motherboard or BIOS Issues
- Current build used outdated BIOS versions:
  - Version 2.20 worked fine for about a week without problems
  - Latest Beta version (3.61) did not fix issue and increased frequency of failures
  - Current stable BIOS version (3.40) reduced frequency but did not eliminate problem entirely
- Tried resetting CMOS and replacing CMOS battery — these didn’t fix anything either
- Still experience successful boots intermittently
NVMe Drive May Need Replacement
- Health is below perfect at ~94%, unsure if this causes boot issues since system runs normally once booted
Power Instability or Faulty PSU
- PSU plugged directly into wall socket without stabilizer or UPS
- Power outages are almost nonexistent in my house
- Tested power stability using OCCT for about 20 minutes — found no issues before stopping due to CPU overheating
- Able to play games like Monster Hunter for hours without problems

If anyone has encountered similar symptoms or can provide advice based on these clues and hypotheses—your help would be greatly appreciated!

Thank you.

Previous Post related to this problem:

strange13930 · April 18

28 minutes ago, Ardentio said:

My Problem Overview:

My PC occasionally won’t boot (no POST). This only happens a few times—not every time—and when it does boot, it works perfectly fine. This inconsistency confuses me as to why the problem occurs.

I have posted about this issue before but unfortunately received no replies. At that time, I tried all the No POST troubleshooting guides from the README, but none completely fixed my PC. However, I want to highlight some clues about why my PC experiences no POST in hopes that someone can help me. Any insight would be much appreciated.

My PC Specifications:

CPU: AMD Ryzen 3600

Motherboard: AsRock B550M Pro4

GPU: XFX Radeon RX 7700-XT

PSU: Enermax Revolution D.F.12 850W 80+ Gold

Memory: Klevv 16GB RAM, dual channel, 3600MHz

Storage:

NVMe M.2 256 GB (Windows only)

WDC SSD 1TB (Game storage)

WD Blue HDD (Data storage)

The Problem:

My PC experiences no POST occasionally—only a few times—but most of the time it boots without any issues. I haven’t figured out why this happens yet.

After updating my BIOS to version 3.40, I noticed fewer no POST incidents compared to version 3.61 which caused more frequent failures. So initially, I thought the BIOS version might be causing this problem.

However, recently it started happening again; just this week alone I've experienced four consecutive no POST events.

To get my PC to turn on after a no POST event:

Sometimes restarting using the front panel button works once after several failed attempts (rarely help).

Turning off and then turning on again via front panel helps boot two or three times (sometimes help).

Power cycling has a higher success rate but still isn’t guaranteed; sometimes I need to power cycle twice before it boots successfully.

Some Clues That Might Help:

Debug LED Behavior

My motherboard has Debug LEDs for Boot, VGA, DRAM, and CPU status indicators.

When my PC boots successfully: The last two LEDs lit are BOOT followed by VGA.

The BOOT LED stays on until the motherboard logo appears; then both BOOT and VGA LEDs turn off together.

When experiencing no POST:

The BOOT LED turns on then off,

Followed by VGA LED turning on,

Then BOOT LED turns back on again, resulting in failure to boot.

(I have attached a video showing this debug LED sequence during a no POST event.)

SSD M.2 NVMe Health

Using OCCT software to check health status of my NVMe drive containing Windows shows around 94% health. Despite not being at full health:

It still functions normally,

Command Prompt checks report its status as OK.

(Screenshot from OCCT is attached.)

Random GPU Low Performance While Gaming

Not sure if it's hardware or game-related bug:

In Monster Hunter Wilds — runs fine with normal GPU performance.

In Tavern Master — experienced very low FPS; GPU usage dropped drastically (~10%) with power consumption around 60–75W instead of usual ~70–80% usage at ~150–200W power draw during normal operation.

My Hypotheses About What Might Be Causing This:

Motherboard or BIOS Issues

Current build used outdated BIOS versions:

Version 2.20 worked fine for about a week without problems

Latest Beta version (3.61) did not fix issue and increased frequency of failures

Current stable BIOS version (3.40) reduced frequency but did not eliminate problem entirely

Tried resetting CMOS and replacing CMOS battery — these didn’t fix anything either

Still experience successful boots intermittently

NVMe Drive May Need Replacement

Health is below perfect at ~94%, unsure if this causes boot issues since system runs normally once booted

Power Instability or Faulty PSU

PSU plugged directly into wall socket without stabilizer or UPS

Power outages are almost nonexistent in my house

Tested power stability using OCCT for about 20 minutes — found no issues before stopping due to CPU overheating

Able to play games like Monster Hunter for hours without problems

If anyone has encountered similar symptoms or can provide advice based on these clues and hypotheses—your help would be greatly appreciated!

Thank you.

Previous Post related to this problem:

It’s something with the Gpu, is it still under warranty? Are your drivers up to date and have you tried different pcie slots and pcie power cables?

Ardentio · April 19

9 hours ago, strange13930 said:

It’s something with the Gpu, is it still under warranty? Are your drivers up to date and have you tried different pcie slots and pcie power cables?

Thank you for your response and taking the time to help. Could you please elaborate on why you think it might be the GPU? I am able to play relatively graphics-intensive games without any issues. I initially thought the problem was related to booting, such as BIOS or Windows drive.

I have updated all my drivers, including motherboard and GPU drivers. My GPU is still under warranty, so I sent it back to the store where I purchased it. They tested the GPU and said it is performing well.

I even brought my entire PC to the store for testing, but since the problem doesn’t occur consistently, it booted perfectly several times there. It also boots fine at home multiple times before suddenly experiencing no POST again.

Thanks again for your insight—I really appreciate any advice you can offer!

strange13930 · April 19

5 hours ago, Ardentio said:

Thank you for your response and taking the time to help. Could you please elaborate on why you think it might be the GPU? I am able to play relatively graphics-intensive games without any issues. I initially thought the problem was related to booting, such as BIOS or Windows drive.

I have updated all my drivers, including motherboard and GPU drivers. My GPU is still under warranty, so I sent it back to the store where I purchased it. They tested the GPU and said it is performing well.

I even brought my entire PC to the store for testing, but since the problem doesn’t occur consistently, it booted perfectly several times there. It also boots fine at home multiple times before suddenly experiencing no POST again.

Thanks again for your insight—I really appreciate any advice you can offer!

If you already got it checked then it’s not the problem. The reason I thought it was the Gpu was because the vga light is for Gpu related stuff. Do you have different power cables you can try?

Ardentio · April 19

4 hours ago, strange13930 said:

If you already got it checked then it’s not the problem. The reason I thought it was the Gpu was because the vga light is for Gpu related stuff. Do you have different power cables you can try?

I have replaced the cable and changed its slot on the PSU. I also reset the BIOS settings again, but this time I disabled the XMP profile and CSM. The PC is able to boot for now. I will monitor to see if the problem persists. Thanks for your advice.

Ardentio · April 26

Update: Issue still not resolved.

I have replaced the PSU cable, reseated all components, reinstalled Windows, and reinstalled all drivers. I now suspect a bad GPU driver is causing the problem.

Here’s why:

After reinstalling Windows (before installing the GPU driver), my PC could boot and restart multiple times without any issue while installing motherboard drivers and adjusting UEFI settings.
While installing Adrenalin 25.3.1 (WHQL Recommended), all monitors disconnected mid-installation. I had to restart the PC using the front panel button, but it failed to POST. After shutting it down again, only one monitor reconnected (before installing the GPU driver, all monitors worked).
I entered Safe Mode, used AMD Cleanup Utility, and reinstalled the GPU driver using Adrenalin 24.12.1 (WHQL Recommended), but the issue still not resolved.

Current behavior after reinstalling Windows:

I no longer need to power cycle the PC; shutting down and turning it on normally usually works.
Sometimes, even when the Debug LEDs suggest a POST failure, the PC can still boot (the motherboard logo appears when the Boot LED lights up), though it still occasionally fails to POST.
Restarting the PC often results in no POST. If I restart into UEFI, it enters UEFI settings fine, but fails to POST after exiting. Shutting down and powering on again gives a better (but not guaranteed) chance of booting.

Additional observations:

I’m still confused about which part is causing the issue. Once the PC is on, everything works perfectly — gaming, streaming, benchmarks, and stress tests all run without any problems.
I tried changing various settings (Fast Boot, UEFI Trusted Computing Support, Secure Boot, CSM, etc.), but none of them fixed the boot issue.
I would like to ask: will repeatedly pressing the restart button or using a single press of the power button to shut down when the PC fails to boot damage my hardware?

Note: I sometimes refer to BIOS, but my system is actually using UEFI (just in case that's relevant).

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PC Won’t Boot Sometimes: Debug LED Clues - Seeking Advice

My Problem Overview:

My PC Specifications:

The Problem: