SQL 7.0 Error 18452

I have created a database in Access 2000. I have upsized it to SQL 7.0. Created a File DSN connection to the database for my network users. I just installed Service Pack 3 for SQL 7.0 and now my network users cannot log into the database. The error message states:
Error 18452 Log in failed for user null, reason not associated with a trusted SQL server connection. How do I fix this? Please help. Thanks for your time.