ok, this means she used a local account, which cannot have the password ***** If there was an email address we could look at resetting it online, but this is not possible.
The only way to remove it is to do a reinstall of windows. This will remove all the data but you cannot avoid this, it is the whole reason for the security.
To do the reset.
On the sign in screen, hold the left SHIFT key on the computer and with it held, click on the power icon and click restart.
Keep shift held down until you are at a menu, then release.
Then click on Troubleshoot, then Reset My PC.
You must choose the option to remove all data.
Let this complete and when it has, windows will be reinstalled and will take you through the setup so you can set it up again and use it just like a new computer.
Let me know please how you go.