Weird problem this morning! (Not a crash/BSOD)

I was using my PC as normal, browsing, checking emails etc. Then I decided to play a Windows Store game (Mortal Kombat 11), which I have played many times.
The game went through the usual splash screen, but then the screen went completely black. Not off (the power indicator was on - white LED). The game was still running (I could hear the audio until I hit ALT-F4 to close it). Screen stayed 'on' but black so no desktop.

Shut the PC down and powered off the PSU - screen still 'active' (white power light on). Disconnected the Mini DP cable from the GPU. Normally at this point I'd get a message on the screen that there was no input detected/no DP signal, but again just black but 'on' as if it still had an active input. When the PC is asleep/off the monitor goes into standby normally.
Reconnected the DP cable.

Unplugged the monitor, plugged it in again and it came back on. It did the initial power-on thing, said there was no input signal from DP then went into standby as it should (orange light).

Powered on and rebooted PC, all fine again. The game launched without problems.

This has never happened before with any game or other software.
No idea what caused this at all - why would the monitor not go into standby when it had no input to it?

If it happens again try:

• To wake the screen, use one of the following keyboard shortcuts: Windows logo key + P or Ctrl + Alt + Del.

• For a black screen, use the following keyboard shortcut: Windows logo key + Ctrl + Shift + B.

zbook said:

If it happens again try:

• To wake the screen, use one of the following keyboard shortcuts: Windows logo key + P or Ctrl + Alt + Del.

• For a black screen, use the following keyboard shortcut: Windows logo key + Ctrl + Shift + B.

Troubleshooting blank screens in Windows - Microsoft Support

If your computer is showing a black or blank screen in Windows, these troubleshooting tips could help get your system back up and running.

support.microsoft.com

Click to expand...

First option did nothing as the screen was already awake (I wanted Task manager so I could reboot without an unsafe shutdown).
Still doesn't explain how the monitor thought it still had an input signal and stayed powered on even when Windows wasn't running and the DP cable was out!

Sometimes live kernel events are recorded into the event viewer.


If live kernel dump files were created this script was created to collect them:

zbook said:

Sometimes live kernel events are recorded into the event viewer.


If live kernel dump files were created this script was created to collect them:

https://www.tenforums.com/attachments/bsod-crashes-debugging/358470d1643456903-batch-files-use-bsod-debugging-gather_additional_dump_files.bat

Batch files for use in BSOD debugging - Windows 10 Help Forums

Information This thread is for use by the BSOD team to store batch files that can be used to collect additional data, fix settings or anything else that is useful in debugging BSOD problems in Windows 10. The way I see it working is the first

www.tenforums.com

Batch files for use in BSOD debugging - Windows 10 Help Forums

Information This thread is for use by the BSOD team to store batch files that can be used to collect additional data, fix settings or anything else that is useful in debugging BSOD problems in Windows 10. The way I see it working is the first

www.tenforums.com

Click to expand...

There was no Kernel event, nothing in event viewer or Reliability monitor. The only thing it recorded was the unsafe shutdown when I used the power button to turn the PC off. The LiveKernelReports folder date hasn't changed.

If you want the event viewer logs scanned then post a V2 share link into the newest post.

It may have been a one time event and you'll be ready if another occurs.

zbook said:

If you want the event viewer logs scanned then post a V2 share link into the newest post.

It may have been a one time event and you'll be ready if another occurs.

Click to expand...

I've cleared the Event logs now, I will keep in mind your suggestions if it happens again. I still don't know how the monitor could still be powered on when it was physically disconnected from the PC.

One of those mysteries

It could be a monitor issue rather than the PC.

Fabler2 said:

It could be a monitor issue rather than the PC.

Click to expand...

Indeed, I will keep an eye on it, and I'll note if it happens, what I'm doing at the time etc.
Also strange was that the game audio was only 2-speaker stereo, normally it's got 5.1 surround.
My Soundcard (Creative AE-5) had for some reason switched to Direct Stereo mode, it definitely was 5.1 yesterday as I was playing FH5 which has surround sound.

The plot thickens....

I’ve had that with an old Big Fish game, I’ll have to check on how I fixed it.
Suggestion is to try Windowed mode Alt + Enter while the game is playing or add -window to the game’s command line switch To see if that shows the graphics.

I'm wondering if this was a precursor to the problem I had on Sunday...

If the monitor didn't give a no signal waring when the computer was shut off then it's the monitor. My guess is that it froze. I don't know how or why but I don' see how doing anything in Windows is going to help.

Fabler2 said:

It could be a monitor issue rather than the PC.

Click to expand...

I'm wondering if it's a monitor firmware issue causing the bug that is known to happen with especially 11, the infamous "blank screen with monitor in normal mode and backlight still lit, but Windows doesn't respond" bug. It 99 percent happens with Chromium-based-Edge. So I wouldn't be surprised if Chromium in general, can cause this as well. Never such incident with Firefox.

The issue seems the most likely to occur with Samsung monitors, based on what I saw on the internet, so far.

Unlike what some people say, Firefox is *not* Chromium/Blink!