Transfer existing Win10 to another account without PW?

My best friend is a pc noob, so i ask (because i have to use it).

She once bought a PC together with her partner and, as I said, she is a noob, her partner set it up and authenticated Win10 (100% legal) on himself / his account and provided it with a password.

Now the two have separated and no longer have any contact with each other.
The PC belongs to her and is also in her possession; he kept his laptop and took it with him.

You do not have to enter a PW when starting up the PC, but can e.g. Install nothing from the store and recently the PC once asked for the PW =: - o Later on the next time it was switched on - fortunately.

To avoid further annoyance, I would like to help her "transfer" this Win10 to her account at Microsoft without having to reinstall (keep data from other accounts, saves etc.) as long as she is without the PW of her ex- Partners still has access.

Is there a possibility, or is there just a clean reinstallation?
But then without problems, since MS knows and recognizes the hardware, or does it somehow (also) depend on the account?

Thank you in advance,
Franek (and best friend) :-)

Simply create a new account. Of course, it also works without a Microsoft account. So just add a local user. Should be at least one admin. Another then simple user.

Can a new user (with or without an MS account) be created without the admin or his PW being available?
Because that's the problem.

So far, the absent ex-partner of the admin and the PW is unknown.

No. You already need the password.

Shouldn't be a problem.

There would be ways to set a new one. A quick reinstallation might be easier if the data is backed up beforehand.

Without the help of the ex it won't work.

Because he has to log in to his Microsoft account and then remove the hardware or Liezens from his account under licenses. Only then can the Liezens be transferred back to a new account.

In addition, the product key may also be required.

https://www.pc-magazin.de/ratgeber/pc-mit-windows-10-verkaufen-lizenz-aktivierung-microsoft-konto-was-tun-3196484.html

If we had the PW, I wouldn't have to ask the question:-)

Then forget everything I wrote and do as you want to do it.

Have fun

Again briefly:
The admin and the PW are behind the seven mountains
It is not possible to get the PW (so it is a problem)
We would like that the problem would not exist or that there would be a solution without reinstallation; I don't know if and how it works.

After a new installation and logging in with the account of my good friend, will it work without any problems because the license depends on the hardware, which is unchanged?

Or does the license depend on the account?

Uff!
So not even reinstalling and logging into the (current) owner's account would solve the problem without having her ex with her?

Where the key is located is unfortunately not known because it was custom built.

Neither. It is a normal user license.

Reinstall. Possibly. Purchase a Windows 10 key. If important data is on the data carrier in the computer, remove the data carrier and back up the user folder with another computer.

Everything else is time-consuming and may not lead to the goal. And above all, it is a fresh start, at least nothing remains of the past on the computer.

You could try to activate the local administrator account and log in with it, instructions can be found via Google thousands. Can't somehow export saves? I don't know about computer games. The savegames are of course not available in the admin account.

Without an ex-boyfriend and without a key, all that's left is:

1) Back up data externally (and the required drivers)

2) https://www.softwarebilliger.de/betriebssysteme/windows-10-pro-64-bit-dvd-coa/?c=13

3) Format hard drive

4) Reinstall Windows

5) Reinstall drivers and programs

6) If necessary, restore the backed up files