How can I change from SQL Server Windows mode to mixed mode (SQL Server 2008)?

Question

I have installed SQL Server 2008 Express Edition, but by mistake I kept the Windows authentication mode.

Now I want to change that to SQL Server mixed mode. How can

Answer 1

I had no success with other attempts on a SQL Server 2012. What I did was use SQL Server Management Studio to generate a script to change the value, and got this:

USE [master]
GO
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'LoginMode', REG_DWORD, 2
GO

After that, I enabled the sa account using this:

ALTER LOGIN sa ENABLE ;
GO
ALTER LOGIN sa WITH PASSWORD = '' ;
GO

...then, I restarted the service, and everything worked!