how to remove a domain from the list

From: James (jgrace_at_digitelusa.net)
Date: 06/22/04 

Date: Mon, 21 Jun 2004 21:31:27 -0400

i have old domain and a new domain.. recently the old domain dc crashed and
we moved the rest of the user over to the new domain.. but we still have
the old domain in the drop down list.... what can i do...do i have to build
a domain and name it the name of the old domain dc and them dc promo......
is there a easier way please