Desktop Boot and Lockup

How do I get out of this boot loop?

I unplugged the computer last night after shutting it down. This morning I plugged it back in and restarted it. About a week ago, Windows did an automatic update, but it started up fine several times after that. After the HP logo, it went into Automatic Repair, the Diagnostics, and then gave a blue screen with "Automatic Repair Your PC did not start correctly"

I tried restart, but it kept going back to this screen (and still does). I clicked on advanced options. The "Continue" option looped back the the blue screen. I do not have a device to use as an alternate boot device. I went to the "Troubleshoot option several times, Startup Repair did not work. I tried nearly all the the Startup Settings, none worked. I tried many of the UEFI Firmware Settings, and did a long check on hardware (took >3h). Everything checked fine (memory, both hard drives, etc.). I have no system restore point to reset to. 

I reset the boot order to use a legacy boot, but as I had no legacy boot device, this did not help. So I set it back the the UEFI boot order (after resetting the safe boot protection).

I followed all of the virtual agent instructions. Hard reset did not work. CMOS reset did not show reset message (I tried several times, holding the keys 2, 3, 5, 8, and 11 seconds). BIOS reset made 8 beeps, but even after 15 minutes, the BIOS screen did not appear.  There were no external devices attached, and the hard reset did not work again.

I conclude that there is not hardware problem, so there must be a software problem. Is there some way I can find/fix this wtihout having to reset the computer? Or is there a way to save all my files (many GB worth) so I can reset without losing files? Computer has a wireless connection, but this does not seem relevant to this problem...