Looks like the added stress of the update pushed your C-Drive over the edge, and it failed completely.

Since you are a smart-user and have a current backup, I would just clean-install Windows-10. Replace all OS and software, and verify your hardware is still good.

If it can make it through a complete Windows-install, there is a good chance it is fine. Of course, the laptop first needs to pass ePSA Diagnostics. If not, you replace the hardware  (C-Drive with a new SSD, etc. ) and try again .

https://www.dell.com/community/XPS-Desktops/XPS-8940-new-out-of-the-box-intermittent-crashes/m-p/8142183/highlight/true#M68592

First of all run diagnostics (tap F12 immediately at boot) and watch for any errors especially HDD/SSD errors. Was the update a Windows only update or was a BIOS update included? The drive is not detected in the boot order and that could be corrupted Windows files. The BCD or MBR could be missing or damaged. This web page has more information on their recovery. And do not use RUFUS to create a bootable installation flashdrive. The Windows media creation tool on this page should be all you need.

To create the USB bootable Windows installation media, you will need  to create the USB drive using the Microsoft creation tool.

A lot of people make the error of putting the installation ISO image on a bootable USB stick, or extracting all the files from the ISO and using another tool to make the USB stick bootable, rather than using the creation tool to create the USB installation media.

I am not saying that is what you did, but it's a common mistake.

You will need another working windows machine to create the USB installation media using the Microsoft provided tool. 

Create Windows 10 installation media. 

Once you have that, you can use the one time boot menu by using F12 key during POST, to directly boot from the USB stick.

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@pd993 wrote:

Plus, I want to note that, to record the Windows image, I used Rufus and the original program 

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No.

Do like @Vanadiel  suggests (on a working computer).

Then, F12 on boot and do a One-Time-Boot of that USB-flash-drive.

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@JOcean wrote:

First of all run diagnostics (tap F12 immediately at boot) and watch for any errors especially HDD/SSD errors.

      @pd993 F12 / Diagnostics = there is no error on the ssd, and all indicators are normal

Was the update a Windows only update or was a BIOS update included? 

      @pd993  no, it was a normal Windows update, I updated the BIOS later, thinking that it would help me somehow


The drive is not detected in the boot order and that could be corrupted Windows files. The BCD or MBR could be missing or damaged.

      @pd993 I agree with you, this is the main problem, but for starters, I would start the usb image. And then I'll get the instructions from the link.

And do not use RUFUS to create a bootable installation flashdrive. The Windows media creation tool on this page should be all you need.

      @pd993 OK, I forgot about Rufus.Only here with the Media Creation Tool the same thing, I will attach a screen for understanding.

DiagnosticsMedia Creation Tool

unfortunately the Microsoft Creation Tool does not help(( the same thing, eternal loading, tried it on legacy in uefi - unsuccessfully.

does not work

Thanks for your time, I'll try your advice.

same, no change

You can also try a CMOS reset by removing and reseating the CMOS battery.

Hi @pd993  evidently the battery did not have more than the minimum 15% charge, to allow laptop to install update during mains power failure. Never update over the internet. 

Your best fix is to get M.2 drive card with generic Windows 10 x64 preinstalled (from eBay, etc.). This will be your new OS(C:) boot drive and will get system specific drivers from the internet. There should be no problems booting automatically into Windows. If system does not recognise new OS(C:) boot drive, hold down F12 to enter boot menu and assign your new drive as first on the boot list. 

When system up and running, install your original drive in other slot to see if any of your personal files can be found.