WSUS cannot connect to database

I was using WSUS on Windows 2000 SP4 server using MSDE database but now i have built 2003 SP1 server which uses SQL 2000. I have installed all required hacks ans fixes so that SQL version/patch level matches my previous MSDE installation.msdb databases have been restored in new SQL installation and WSUS has created the SUSDB database within SQL as well but now when i am trying to access WSUS admin page then i am getting an message saying "Error connecting to the Windows Server Update Services database". I have gone through event log and i see this:

Connection to database failed. Reason=Cannot open database requested in
login 'SUSDB'. Login fails.
Login failed for user 'NT AUTHORITY\NETWORK SERVICE'.. Connection string:

I want to know if i can do anything to to get back access to WSUS admin page?

I will like to inform you that database "user" account is associated with SID, to the SQL Login because of which when database is restored to another server, SIDs gets changed. Anyways you can go through below article for understanding system stored procedures and for sorting out the issue you are facing.
PRB: "Troubleshooting Orphaned Users" Topic in Books Online is Incomplete