My second Windows operating system no longer boots?

I have two Windows 10 operating system on one laptop,

I could always choose which Windows to start beforehand,

Since I wanted to make the PC fresh again, I reset an operating system via Windows settings, since then it no longer recognizes the second operating system and the original recovery was also deleted by the reset… The only way is if it would boot, I could from Reset Windows from the original, then I have the original operating system again, which was previously on the laptop

Maybe there's software that makes an operating system bootable again?

Via (sysdm.cpl) the only recognizes a Windows operating system

I have access to the hard drive

P.s. Recovery mode test also no longer works…

Unfortunately, the boot process was changed massively by the 2004 version. Unfortunately, you do not write which version of Win 10 you have.

With autoupdate in 2004.

Please read through what has changed. Unfortunately, a "simple" solution is rather unavailable.

The original operating system was previously Windows 8, with (media creation tool) I did it on Windows 10 Pro.

and the other operating system was Windows 7, (media creation tool) I did it on Windows 10 Pro.

I added three new photos.

Hm, i would say sorry! -

'format c:'

In the best case, Win 10 has completely reinstalled itself and your computer is full of system backups. Or it would have written about it. Then the handbrake will be permanently applied to all processes.

Why do you want so many operating systems? Make NTFS with Win 10 over all disks and install the other operating systems as virtual machines.

Get a large external hard drive, drag everything over and flatten the computer down to the zero sector. Then raise the treasure of the backup and dig the rest. Then you have a new backup HD.

The old keys all work! You don't need an "update".

No backups on the disk are just the only standard backup of Windows, if you reset it and when I reset it, I chose not to take old private things like apps and software, so it is freshly installed without backup and old Windows 7 also deleted itself automatically after 30 days…

no matter what Windows I was in before, the disk had had C:.

there are not that many = D With virtual machines, the graphics are too weak, they need it for Adobe video editing, YouTube stream, etc. And the other Windows for visiting if someone wants to surf or a friend, etc… Wanted to keep everything separate

I lost the original key sticker and I have no guarantee…

is there no other way to make disk D: bootable again? Because on disk D: Windows is still installed, it just does not start…

Get from Google how to read the key in a running system and write it down on paper.

For the girlfriend, Win 2004 now has a completely new possibility: You can now create a surface where you can "just surf". I.e. You create a guest user and cut the rights. Apparently others also had a need.

ad backup: you don't see these files immediately, you ask yourself in a year what kind of strange directory that you accidentally found. That made the record full year and day.

and: a new key only costs 8 euro. If you know where to look. I bought it in Hong Kong and it worked great. Came immediately by email, was accepted on the first try.