If ever you have the message that the login failed it may be because of an orphaned user.
Run this to check what orphaned users you have.
EXEC sp_change_users_login 'REPORT'
Then run this to fix it. Where ‘LoginName’ is the login and then the user it is attached to.
From this website http://mcpmag.com/articles/2011/02/17/fixing-sql-server-2008-database-orphans.aspx