Windows 2003 server and AD

Was the domain controller that died a Windows 2000 domain controller?

I am assuming that you moved or seized the roles to the new domain controller. You will need to perform the following:

Backup the system state and the SYSVOL. You should already be doing this for disaster recovery purposes. Backup and Recovery are covered in the Windows 2000 Operations Guide, which can be found here:

http://www.microsoft.com/technet/prodtechnol/windows2000serv/technologies/activedirectory/maintain/opsguide/part1/adogd03.mspx

A meta-data cleanup of Active Directory to remove any associations with the old PDC. Details for that are here:

http://support.microsoft.com/kb/216498

Next, you will need to prepare your forest and domains for the upgrade to Windows 2003. Details on these operations are to be found here:

http://www.microsoft.com/resources/documentation/WindowsServ/2003/all/techref/en-us/Default.asp?url=/Resources/Documentation/windowsserv/2003/all/techref/en-us/w2k3tr_addcp_what.asp

Unless you are perfectly certain there will be no issues with Windows 2003 implementation, do not raise the forest or domain functional levels from the defaults. Details on this are here:

http://www.microsoft.com/resources/documentation/WindowsServ/2003/all/techref/en-us/Default.asp?url=/Resources/Documentation/windowsserv/2003/all/techref/en-us/w2k3tr_fnlvl_intro.asp

Upgrading your forest and domain to Windows 2003 and installing your first Windows 2003-based Active Directory domain controller, will NOT delete your users, as your current domain controller will still have that information.

Best of luck on your upgrade.