A. It is not possible to have 2 PDC's in a domain so assuming the machine crashed, i.e. has not been demoted to a BDC before being shutdown, then when it starts it will still be configured to be a PDC
- Start up the old PDC machine
- Logon to the machine as an Administrator
- Start Server Manager (Start - Programs - Administrative Tools - Server Manager)
- The machine will still be described as a Primary Domain Controller, however its icon is just a wire frame and it is not acting as a PDC, i.e. it does not authenticate logons
- Select the machine, and from the Computer menu select "Demote to Backup Domain Controller"
- Click "Yes" to make the change
- Once the machine is a BDC, click on the computer again and from the Computer menu select "Promote to PDC"
- Click "Yes to make the change
- Server manager will then automatically demote the temporary PDC back to its BDC status and promote this machine back to the PDC