Changing authentication mode for Sql Server express edition

One way of doing it is through sql server management studio explained over here

http://msdn.microsoft.com/en-us/library/ms188670.aspx

But if you haven’t installed the management studio than in that case you need to make following change in the registry

HKEY_LOCAL_MACHINE / SOFTWARE / Microsoft / Microsoft SQL server / MSSQL.1/ MSSQLSERVER/ LoginMode

Click on it change it’s value from 1 to 2.

Then Restart your sql server service !!!

After you have done this you need to enable you sa account for sql server authentication for this follow these steps

1) Open SQL Server Management Studio Express and Login
2) In Object Explorer, click Security followed by Logins
3) Right click sa user and select Properties.
4) Uncheck Enforce password policy
5) Select Status. Click the Grant and Enabled radio buttons. Click OK
6) Restart your database server and select restart.

That’s it

Source : http://nishantrana.wordpress.com/2009/01/07/changing-authentication-mode-for-sql-server-express-edtion/