Steps to restore a system state for Active Directory

How to restore for AD? you cannot restore the System State Data while the
Active Directory is running. Thus, you need to boot the computer into Directory
Services Restore Mode. This is similar to Safe Mode and will not start the Active
Directory. Be aware that during this time the machine won't act as a DC and won't
perform functions such as authentication. To restore the System State Data after
starting the computer in Directory Services Restore Mode:
1. Start NT Backup.
2. Select the Restore tab.
3. Select the backup media, and select System State.
4. Click Start Restore.
5. Click OK in the confirmation dialog box.
6. Reboot the computer into normal mode.