FAQ valid for both Windows Client and Windows Server
1 – Install and boot from a Windows ISO (Windows 10 or higher)
2 – When the Windows Setup appears, press SHIFT + F10 
3 – A command prompt windows will appears, type the following commands:
4 – wmic logicaldisk get name
(Allows to view the disks mapped on the machine.
You have to identify the one with Windows installed)
5 – move d:windowssystem32utilman.exe d:windowssystem32utilman.exe.bak
6 – copy d:windowssystem32cmd.exe d:windowssystem32utilman.exe
7 – wpeutil reboot
N.B. : in this example I used the letter “d:” but could be different.
The commands above modify the EasyAccess function button in the Windows login page.
When the button is clicked, a command prompt will be opened instead of the EasyAccess functionality.
Once the command prompt is open, it’s possible to reset the administrator local account or add a new user with administrative permissions with the following commands:
8 – net user administrator nuovapassword
If the local administrator account is disabled, it’s possible to enable it with the command:
net user administrator /active:yes
If you wish to create a new user, type the command:
net user username userpassword /add
9 – To add the new user to the local administrators group type the following command:
net localgroup administrators username /add
10 – Now you can log into Windows with the new user you have just created