Supervisor Password

I have a client with Norton AV 2006 on his system, but everytime we try to access NAV it prompts us for an account name and password. They only have the one computer and he (the owner) nor his secretary claim to have never setup the NAV and have no clue as to the password. It has an account name of "Supervisor" listed in the dialog box.

 

How can I find this information for him? This problem has caused a shut down of his accounting software and he needs to get that back up and running ASAP. Please help!

 

Diane Koers