Login Resolution

Friends
I have one SQL server2000 which have Mixed Mode authentication.It is working fine in PC which server instance is situating.But I have another PC which having connectvity tools of SQL Server.When I am trying to access SQL Server from the second PC through SQL authentication access getting denied.In the same time if I am accessing any of first PC's Folder using it's administrator password.Then if try with SQL authentication I am able to connect with SQL Server in the First PC from second PC .Please note SQL server instance is not in windows authentication mode .What may be the problem.Please suggest me a resolution

Thanks in Advance
Filson

What is the error logged in the SQL Server errorlog?

Thanks
Laurentiu