Hello!
There's a laptop with Win8.1 64bit. There was just one user which was the Administrator. Due to the fact that the person using it had no clue what is he installing or opening the administrator rights were denied by changing the account type to a standard user using Win+R "control userpasswords2".
Now there is no Administrator and its not possible to install any software or create another user or anything.
I have tried the different options without any success described here: eightforums.com/tutorials/9650-built-administrator-account-enable-disable-windows-8-a.html
Any suggestions?