1.  Log in to the OS as administrator.

2.  If yours is a default instance of SQL Server, check the following value to make sure it set to a 0 (if you change this value, you must restart SQL Server):

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\MSSQLServer\LoginMode

3.  Run this from the command line to update the 'sa' password to NULL:

      osql -E -Q "EXEC sp_password NULL, NULL, 'sa'"