SQL Sever 2000 And 2005 On Same Machine

Hi,

I am trying to create a connection string that will connect to a SQL Server 2005 Registration on a remote machine.  I have a SQL Server 2000 registration (installed) on the same machine and so I think there may be a conflict.  The SQL 2005 registration is denoted as HARDYSQL5 and the 2000 registration is merely HARDY (the machine name).  I need to connect to a database on the HARDYSQL5 registration but I am not connecting.  I have tried various connection strings but none have worked.  I get a Login failure.  I think this is red herring because I doubt its even finding the database.
I can connect to the 2000 db with:
"Server=HARDY;Database=Perimeter;UID=use;pwd=example;"

But its fails with the following, for example:

"Server=HARDYSQL5;Database=Perimeter;UID=use;pwd=example;" 
"Server=HARDYSQL5;Database=HARDYSQL5Perimeter;UID=use;pwd=example;"
"Server=HARDY;Database=SQL5Perimeter;UID=use;pwd=example;"
 I'm gon go nuts.  What am I doing wrong?
 Thanks.