Random Black Screen on Laptop 17by4063cl, Win11

[KenSm]

Getting random black screen crash, 1- 5 times a day on 17" Laptop, 17-by4063cl.  Keyboard is inop.  Only way to recover is to force power down and power back up.   Screen goes dark.  On one occasion, there were blinking lines flashing on about the first 3" from the top of the screen.  All other times laptop just goes down.  I don't think it's just the screen only that goes out, as I've had a radio station playing, and it stopped too when the screen went black.  This is a 2021 factory refurbed unit that was not used regularly until maybe 6 months ago.  It has not been modified since purchased.  It has 12MB ram, 11th gen I5, 2.40 GHz, 1 TB HDD.  Initially it came with Win 10 home, now has Win 11 home - upgraded in the last several months.  As a refurb, the 90 day warranty expired in 2022.   It sits on a desk all day, does not travel, & sits on a tilted laptop stand with cooling fans under it.

I've run most/all the HP Support Assistant diagnostics and they show that all is good.  One of the things I have noticed is that I can run the HP diagnostics for hours at a time, and the laptop never fails.  It seems to me that these failures have started after the migration to Win 11, but I can't be certain of that.   When it fails, I'm typically running with the Firefox browser with a few tabs open.  Also running with Thunderbird email client running.  All software is at the latest update level, as I generally keep things current.  

This ticket was created on that very laptop, as it kept running long enough to get it entered.  

Any advice would be appreciated.   Thanks!!     

[KenSm]

Bios is at 09/05/23.

[KenSm]

Some pictures .....