How to restore a new WS 2012R2 domain after a failed migration?

Question

Domain Name System

Migrated AD from Windows Server 2003R2 to Windows Server 2012R2.
The migration seemed to be successful, but the last stage ruined everything and everyone, namely:
dcpromo in 2003 could not determine the domain controller, and I, well done, instead of thinking carefully, launched dcpromo / forceremoval , which actually killed everything in the snap -ins 2012R2, they are empty!
For example, when running Active Directory Users and Computers , the message pops up: Name
information could not be found for the following reason:
The specified domain does not exist or cannot be contacted
Contact your administrator and verify that the domain is configured correctly and that the domain is working.
How to restore everything?

Answer 1

Administration (from admin) --> group policy management,
find and enable the following policy:
All users turn on machines and are pulled up automatically according to the data entered in AD. It's not safe, the solution is for the here and now .

Answer 2

dcpromo /forceremoval...
restore state from bcp, no options.