Add user from cmd with admin writes and change password for admin account

To add a new user open cmd with administrator writes :

net user Username /add password

The user is a limited user. To give administrator writes :

 net localgroup administrators Username /add

To delete a username :

net user Username /del

To change the password of a user if you cannot access any windows account.
Boot from a usb and access the windows partition.
Go to C:\Windows\System32\
rename sethc.exe to sethc_.exe
copy cmd.exe and rename it to sethc.exe 

Boot to windows, when at login screen pres SHIFT key 5 times, and instead of the sticky keys message you get a cmd with admin writes.

Next change password with :

net user Administrator 1234