To set up a SQL Server service to log on under a different user account
Important If Microsoft Full-text Search is installed on the computer, do not change the MSSQLServer account information in the Services Control Panel applet. While the Microsoft Search service is always assigned to the local system account, it keeps track of the MSSQLServer service account. You must change the MSSQLServer service account in SQL Server Enterprise Manager for the Microsoft Search service to stay in synch.