here are the steps you need to prepare to restore an active directory domain controller after a crash..

how to perform an authoritative restore to a domain controller in windows 2x
http://support.microsoft.com/?scid=kb%3Ben-us%3B241594&x=11&y=19

restoring a domain controller through reinstallation
http://technet2.microsoft.com/windowsserver/en/library/2f44ad0e-f84d-47a2-956b-df3f8554ea541033.mspx?mfr=true