Configuring SQL Authentication can be tricky at times, and this is a great article that goes over the two types of authentication in SQL. I find some programs interface better with direct SQL authentication when Windows Authentication fails for any reason.
Note: This article is taken from http://kb.gfi.com/articles/SkyNet_Article/How-to-configure-SQL-Server-2005-2008-to-accept-SQL-Authentication and all credit goes to them for the writing. I’m posting it here simply as a reference in case there _site changes the above link. _
In order to use SQL Server authentication, you must first configure your server using the steps below.
Once you have walked through configuring SQL authentication, you can now change your instance to the type you need.