Create database problem.. Please help

I am a newbie to Oracle 7.33 and I need help to create a database.

I am trying to create a database 'DOG' by the following:

    Copy Initorcl.ora to Initdog.ora and changed db_name and Control_files lines.

    Use NT Instance Manager to create new instance with SID=DOG, enter path for Parameter

          Initialization file and under Advanced changed database name to DOG. New instances are created with no errors.

When I launch Instance Manager and log in (INTERNAL) with service name of DOG, I got the error

    ORA-12154:TNS: could not resolve service name What am I doing wrong? Do I need a more descriptive name then DOG?

Thanks in advance for any help. Please Email me directly as I don't have a reliable connection to this news group.

Under NT services panel I have the following two services, both started:  OracleStartDOG
 OracleServiceDOG

Under Instance Manager I have the following:

   DOGS
    Services Started Automatic
    Instance Started Automatic

   ORCL
    Services Started Automatic
    Instance Started Automatic Received on Tue Feb 17 1998 - 00:00:00 CST