HP Envy 23 does not boot up

[Vent19]

I have a HP Envy 23 (d260qd) touch smart computer that I use every day.  On morning recently, when i hit the power button, instead of booting, the computer said it was initiating the Automatic Repair function.  It then proceeded to indicate that it was diagnosing the problem, and then tried to repair the problem, but finally the blue screen showed up indicating that the "PC did not start properly."  After running through all the options in advanced troubleshooting, I restarted the PC and segued into the HP diagnostic screen where i ran all diagnostics, even the long extensive one (more than 4 hours), and all diagnostics passed successfully.  I downloaded a Windows 10 media file to establish a bootable USB thumb drive and a DVD, but neither worked, even though i had disabled the security boot and enabled the legacy (as i had read on one of these pages).  I also tried changing the boot order... but nothing seemed to work.  Any suggestions?  Would buying a new version of Windows 11 and starting from scratch work?  This PC has all my important files on it and sadly i have not kept up with backups.  I am able to get to the command prompt and tried a few things from there but still unsuccessful.  I would think that with all the diagnostics passing successfully and able to communicate with the troubleshooting part that the PC is still viable.  Would love to know what anyone else thinks or ideas to fix.  Thanks much.

[Vent19]

In response to Lynn240:  Appreciate your help and support.  I discovered that I could use the command prompt with "x copy" to retrieve my important files and have been doing so, using a Terabyte external drive connected to USB.  That was important to me to do first, as my limited knowledge about computers may result in making the start-up problem worse, so I wanted to save what I could first.  Second, I am going to try to retrieve the Windows Product Key that is imbedded in the Bios (or so I have been told) so when I attempt to reload Windows 10, I will have what I need to move it along.  If you have advice on that effort, I would appreciate your guidance.  Once I have the key, I will try the downloaded Windows ISO file via USB to see if I can restore the system.  If not, I guess I will buy a repair & recovery media from Amazon to see if that will do it.  Meantime, my plow tractor won't start, my truck battery is dead, and my outgoing mail server got screwed up (I suspect a windows update, but then I blame them for every computer problem anyway).  Thanks again for your help.