Now type net user administrator /active:yes this will tell Windows to enable the hidden default build-in Windows Administrator account. Log in to an existing user > Start Menu > type “cmd” find “ Command Prompt” and right click make sure launch as “Administrator”. In Windows 8.1, you can enable the default Windows Administrator account with the following steps. If you are a Mac or Linux user, Windows’s Administrator is more or less the equivalent of the root user for UNIX/Linux system. Administrator account is used for making system wide changes that could affect all other users on the computer. By default, the build-in Administrator account is hidden.

There is always an hidden Administrator account associated for every Windows since Windows Vista.