right click on My computer >> propreties >> computer name
within this field you'll be able to see whether your PC belongs to a domain.
if your computer belongs to a domain you want to change that to a workstation from the "change" menu (give it any name).
check local users via
press "Windows Key" + "R" >> type "control userpasswords2" and hit enter, from there you'll be able to manage local users and leave the ones you want.