SQL Server 2005 : Reset SA Password

- Open the SQL Server Management Studio.
- Open a New Query.
- Copy, paste, and execute the following:

GO
ALTER LOGIN [sa] WITH DEFAULT_DATABASE=[master]
GO
USE [master]
GO
ALTER LOGIN [sa] WITH PASSWORD=N’NewPassword’ MUST_CHANGE
GO

(where NewPassword is the password you wish to use for the sa account)