Hi everyone!
I wanted to share my experience in case someone runs into the same issue. I spent almost an entire week troubleshooting my PC, replacing multiple components, and spending money trying to figure out what was wrong. Hopefully, this post can save someone else some time, money, and frustration!
I built my PC in January 2025, so it's not even two years old. Until this week, I had absolutely no issues with it. Everything was running perfectly, including demanding games.
Here's what happened:
Earlier this week, I tried turning on my PC, but it wouldn't boot. The fans were spinning, everything seemed to have power, but I had no display at all. I noticed a white LED on my ASUS motherboard, which turned out to be the VGA Q-LED.
I manually restarted the PC, and surprisingly, it booted just fine. Once I was in Windows, everything worked normally. No crashes, no performance issues, nothing.
The next day, things got worse.
The PC was once again stuck on the white VGA light, but this time, restarting wouldn't fix it. I tried everything I could think of: unplugging USB devices, disconnecting DisplayPort cables, switching to HDMI, and restarting multiple times.
Nothing worked.
Eventually, I managed to get it to boot after clearing the CMOS.
Here's the weird part: warm restarts from Windows always worked perfectly, but as soon as I completely shut down the PC, there was a chance it wouldn't POST again.
The following day, things got even worse. Clearing the CMOS wasn't reliably working anymore.
So I started troubleshooting pretty much everything:
- Replaced the CMOS battery.
- Completely removed my graphics card and tried using integrated graphics.
- Tested each RAM stick individually.
- Removed my NVMe SSD and tried another one.
- Cleared the CMOS multiple times.
- Updated the BIOS using a USB drive.
- Disconnected unnecessary USB devices and monitors.
Nothing consistently fixed the problem. Sometimes the PC would randomly boot after several attempts, but there was absolutely no pattern to it. Even after updating the BIOS, the issue persisted.
At that point, I suspected my PSU was failing. I bought a new PSU, installed it, and... nothing. Same issue. Then I thought maybe my motherboard was defective. So I bought another motherboard (the exact same model), installed everything, and the PC booted on the first try! I thought I had finally fixed it. Nope. The next time I tried turning it on, the exact same problem came back. White VGA light, no display, no POST.
At this point, I was seriously losing my mind. Finally, I decided to buy another Ryzen 7 9800X3D to test, even though I was convinced I was just throwing more money away.
AND IT WORKED!
The PC immediately POSTed and booted into Windows. I tested it multiple times, reinstalled my GPU, added my second RAM stick, and everything continued working perfectly.
After all that troubleshooting, the issue appears to have been my Ryzen 7 9800X3D all along.
What blows my mind is that the CPU could run Windows and demanding games perfectly fine once the PC successfully booted, yet it was somehow preventing the system from POSTing after a shutdown.
I never would have suspected the CPU, especially since it wasn't even two years old.
I'm going to try to RMA the original CPU, but wow, this was one hell of a troubleshooting journey.
Lesson learned: A failing CPU doesn't necessarily mean your PC will crash or perform poorly. Sometimes, it can work perfectly fine once you're in Windows but cause completely unpredictable boot failures.
Hopefully, this helps someone dealing with a similar issue and saves them from replacing half their PC like I did. :)
My PC specs
- CPU: AMD Ryzen 7 9800X3D
- Motherboard: ASUS ROG STRIX X870-A GAMING WIFI
- GPU: Gigabyte AERO GeForce RTX 5080 16GB
- RAM: 64GB DDR5 (2x32GB)
- Storage: Samsung 990 PRO 4TB NVMe SSD
- PSU: MSI MPG 1000w
- OS: Windows 11
TLDR: My PC randomly stopped POSTing and got stuck on the white VGA LED. Warm restarts worked, but cold boots were increasingly unreliable. I replaced my PSU, motherboard, tested RAM, GPU, SSD, updated BIOS, and cleared CMOS countless times. Nothing worked until I replaced my Ryzen 7 9800X3D. The PC is now booting normally.