MS SQL Server is case insensitive by default   To make a column case sensitive for a password field is a straight forward process you can do within Visual Studio.  Assuming you are connected to your database, simply browse to the table that contains your users passwords and open the table definition.  Highlight the password column and in the column properties  scroll down to "Collation" select SQL_Latin1_General_CP1_CS_AS.  Save your table.  Your password column is now case sensitive.