Yet another black screen on login

I'm going to start testing today.

I have begun my testing.
Disconnected all USB except K&M. Did not disconnect Ethernet, but WiFi and Bluetooth are off.
Pulling the Ethernet cable would have left me to my Ubuntu box for everything I do daily. It is not set up for regular use. I mostly VNC into it from Windows.

So I guess I'll let this run at least 7 days before I begin plugging anything in again. I'm not sure that even 7 days is long enough; some of these 'events' occurred more than two weeks apart, but the period appears to be decreasing with time.

As for my beloved DAC... well, turns out I can have my DAC and eat it too!
I just hooked up the DAC to my Android phone (through a powered hub to eliminate power drain).
The DAC was regonized by PowerAmp - my main music player on the phone. I wonder whether a hookup to my Ubuntu box would be as easy as with Android OS..

Let me just say that my 'gut' is telling me that this is strictly a Windows problem; not hardware related. That feeling comes from my knowing that it only started after restoring Windows 10 (from the backup created by the Win 11 upgrade) after upgrading to 11 for about a week.

However, I understand the need to follow a logical process of troubleshooting. I also enjoy testing and experimentation.
I think I will be happy so long as I still have my DAC!

Thanks very much for the info w links to in-place upgrade. I never realized that was possible.
I guess that's what I should do if I have the problem now with the USB devices disconnected.
I just created the .iso file - just to make sure I wouldn't run into any problems. I will create a new one at the time I need it - to be sure I have the latest build.

- - - Updated - - -

Well, the problem has recurred twice over the past 24 hours - with only the M&K plugged into USB.
I suppose the next step in troubleshooting would be to start Windows in safe mode. But at this point, I just want my system running properly as quickly as possible.
I have chosen to do the in-place Windows 10 upgrade.
I will probably do that tomorrow, as I need to create a full data and OS backup first.

Thanks for the advice;
I recently cleaned the entire box and keyboard with compressed air.
I have not yet checked the SSD's or memory sticks, but if the problem persists now that I have done the in-place upgrade, that is the next thing I will be looking at.
Another thing I might do is boot to Windows 11 instead of 10.
The computer does not appear to be running hot. I haven't even been playing any games that might load the graphics system.
There is no trouble code (beeping) from the MOBO.
I am completely comfortable messing around inside the box; After all, I did this build.

After the in-place upgrade was completed, I noticed that the screen no longer blanks after about 1 minute when the lock screen is up, if I don't log in. That was kind of odd, as I had the screen saver and set to 20 mins, and power options to turn off the screen after 20 minutes - so effectively I never saw any screen saver, but that was what I wanted.

I guess all I can do now is keep using the machine the way I have been, and wait to see if the problem recurs.

Well, there's at least one comforting note about all of this:
If the problem does turn out to be a hardware issue, I believe that most of my hardware is still under warranty - I did the build in April 2020. Had it not been for the stimulus package(s) most of us received, I would probably still be plodding along with my old system, which is now 9 years old - but still running fine. That's the machine I now have Ubuntu on.

Update 12/10
The black screen is not gone!
The same thing happened yesterday.
I took a look at Windows updates - thinking that an update after the in-place upgrade might be the cause. But apparently that is not the case. The last important updates were 'quality' or security updates released (and installed) in October - after this problem started. So the black screen has been happening since about mid Oct, and those updates were installed about two weeks later.

I opened 'Autoruns64' to see what was being loaded when Windows starts.
I found a driver for my SDR (software defined radio) which is an SDRPlay RSP1. I have owned this radio for about 5 years now, and have never had any trouble with it. But considering that I upgraded the software (and perhaps the driver) at some point. I don't recall exactly when, but it was probably around June or July 2021.
Anyway, fwiw, I disabled the SDR driver.
Now it's yet another waiting game.

One more thought: Since this is a video related issue, maybe I should be looking at NVIDIA, and not Windows.
Perhaps roll-back to a much earlier NVIDIA driver; one that was released before I began having the problem.