This may be obvious, but you also must have a domain account with rights to add a computer to the domain. With the requirements out of the way, let's start with some preparatory, one-time work you'll ...

Add to domain<BR><BR>Note: If you are keeping the same IP, you'll have to remove the computer from the domain in order to avoid IP conflicts in you DCs.

The default Windows 2000 domain policy already allows users to add computers to the domain. If you want to specify a specific user add it to the default domain policy in security settings->Local ...