Joining a Windows Domain

On a Windows 2000 Professional computer that was part of a domain. It is disjoined from the domain by joining it to a workgroup. The computer is renamed, and it has a valid ip address. Also, the old computer name is removed from server manager. In attempting to add the computer to the domain, an error message saying something like “There is no domain controller available” Why does this happen? How can the computer be added to the domain.