If Active Directory gets corrupted, check these resources:

• Active Directory Disaster Recovery
• Active Directory Backup and Restore
• Active Directory Diagnostics, Troubleshooting, and Recovery
• Windows 2000 Safe-Mode Boot and Recovery Console
• Windows 2000 Server Disaster Recovery Guidelines
• How to Perform an Authoritative Restore to a Domain Controller
• Disaster Recovery for Branch Office Environments
• Managing Windows 2000 Disks, Backup and Restore