Win8 how to become an administrator without a user group

There are no users and groups in My Computer Management
It's not a computer administrator.
does not work properly when installing certain software

How to become a computer administrator

Open system drive letter/windows/system32  --Find "cmd.exe"--right mouse---select--"Run as Administrator"   at the command prompt input net localgroup administrators " Your own username "/add Note: View your own username: NET user      carriage return

Ask

net localgroup Administrators "your own user name"/add net user      carriage return is this the case?

Reply

At the command prompt, enter net localgroup Administrators "your own user name"/add

Win8 how to become an administrator without a user group