I have 3 domain controllers, 1. was the main 2008 R2, 2. 2012 R2 current main, 3. 2012 R2 as second. The 2. dc was promoted, etc to become the main, and is verified as the main, and the 1. old main was down graded. When I shut down the old main (1.) every computer loses connectivity to the domain. The old main (1) has now went bad and is disrupting AD services in the environment. I can't bring it back to life. How can I force computers to use the 2. and 3. domain controllers? How can dc 2 see itself as the main?