About sql server authentication

Question

Dear sir,

      I am trying to connect with SQL server 2005 with server authentication but I get an error --

Login failed for user '' ". The user is not associated with a trusted SQL Server connection.

I am already performed following steps ----

"Go to Start > Programs > Microsoft SQL Server 2005 > SQL Server Management Studio 
Right-click the Server name, select Properties > Security 
Under Server Authentication, select SQL Server and Windows Authentication Mode"

login --enabled.

  Please provide me appropriate solution . 

--

Thanks in advance.