Question Booting problems because of Windows Update. [MSI GV62 8RC]

[crstllracing231.alt]

First of all, I updated my Windows 10 for the Insider Program. Then I restarted my computer, and a message shows:

(loading circle)
Working on updates 0%
Don't turn off your PC. This will take a while.


Your PC will restart several times.​

After it was working on updates up to 15%, my laptop restarted. At first I thought it was normal, but then I saw a window with a transparent body (I can only see the title bar) for a split second, then some black screens with this message:

(loading circle)
Attempting to recover installation...

2nd:

(loading circle)
Undoing changes made to your computer...​

It's also looping. My laptop restarts, then back to these screens.
I have searched for a solution but all of them doesn't work and/or unrelated to mine.
I decided to wait, however, for a whole day, but it is still in that state.

I have contacted Microsoft Tech Support and one representative told me to reinstall Windows. I don't want to lose my files. I have tried that but here is the screen that I get.

Windows Setup
Compatibility report

The upgrade option isn't available if you start your computer using Windows installation media.

If a copy of Windows is already installed on this computer (yes I do) and you want to upgrade, remove the installation media and restart your computer. After Windows has started normally, insert the installation media and run Windows Setup.​

Close​

I can't even boot into Windows, how would I reinstall it now?
I used Legacy mode for booting the USB flash drive. Inside was Win 10 version 1903. I also used Rufus for burning the ISO into the flash drive.

I also tried the troubleshooting options from the Advanced Startup Options, but no option works at all.

I then tried the Custom install, but I can't even select any drive to install Windows 10 to, showing "Windows cannot be installed to this disk. The selected disk is of the GPT partition style." I already made my USB flash drive dual boot, but it's still like that.

Is there anything I did wrong, or anything I didn't do? I want to successfully boot into Windows without losing my files.
Also, my laptop is running Windows 10 version 1809.

 

[Lutfij]

You will need to recreate your bootable installer(USB) using Windows Media Creation Tools but at this point of time, after what you're saying, your data on the installation partition is gone. Best learn to back up your critical data before experimenting, especially with Windows 10. What is the make and model of your laptop(SKU)? Are you on the latest BIOS update for your laptop?