Computers are either joined to a domain or they are not. You can either check the computer, or check Active Directory to see if the computer is part of the relevant domain or not.
I see you posted in the SQL 2005 Forum. Which server operating system are you using? If Server 2003 right-click My Computer and go to Properties. Then look in the Computer Name tab for the domain name. If not in a domain it will say a workgroup name instead.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato