It is crucial that the DNS computer name of this computer is registered. Since this computer was a domain controller, you ...

It is crucial that the DNS computer name of this computer is registered. Since this computer was a domain controller, you cannot rename it. If this is not a primary domain controller, you can cancel the Active Directory Domain Services Installation Wizard, rename the computer, and then promote it to a domain controller, if necessary. To rename the computer, right-click My Computer, click Properties, click the Network Identification tab, and then click Properties and modify the Computer Name.