System Administrator (sa) Login
New Information - SQL Server 2000 SP3.
System administrator (sa) is a special login provided for backward compatibility. By default, it is assigned to the sysadmin fixed server role and cannot be changed. Although sa is a built-in administrator login, do not use it routinely. Instead, make system administrators members of the sysadmin fixed server role, and have them log on using their own logins. Use sa only when there is no other way to log in to an instance of Microsoft® SQL Server™ (for example, when other system administrators are unavailable or have forgotten their passwords).
During installation, SQL Server Setup prompts you to set an sa login password if you request Mixed Mode authentication. You should assign a password immediately to prevent unauthorized access to an instance of SQL Server using the sa login.
By contrast, if you select Windows Authentication during installation, assign a password to the sa login after installation to ensure that the sa login has a password in case you later change the mode to Mixed Mode authentication.
Security Note Do not use a blank password. Use a strong password. For more information, see Security Rules.