For Windows users who do not have permission to perform ALTER LOGIN SA enable, the following method can be used to successfully modify the sa password login.
1. Use Run as a administrator to open the command prompt and enter the net stop MSSQLSERVER, which stops MSSQLSERVER running.
2. At the command prompt, enter the NET start mssqlserver/m and start SQL Server 2008 as single-user mode.
3. Log in to SQL Server 2008 with the administrator account.
4. When SQL Server is already in single-user mode and allows only one user to connect, clicking "New Query" will error "Login failed for user." Reason:server is in single user mode. Only one administrator can connect at this time.
5. Right click on the instance name, click "Disconnect", Close "Object Explorer", then click "New Query" to connect, you can use the command ALTER LOGIN SA enable re-open SA account, alter LOGIN [SA] with PASSW Ord=n ' 1234qwer ' to change the password.
6. Now close SQL Server, and at the command prompt, enter NET STAR MSSQLSERVER to start SQL Server normally, and you can log in to SQL Server with the SA account. [/quote]
SQL Server modifies the sa password (without permission on Windows login)