Oracle database domain change

I have two oracle 9i databases running on Windows Server2000. I changed the domain that the server was running on. Everything works except for the database links between the two databases. When I do a tnsping, the service name is resolved only with the old name.
ie databasename.olddomainname. That does not make sense to me since the database is on a server with a new domain name. Can anyone offer some insight as to what might be wrong?