Shortly after I installed MS SQL Server 2008 on my machine, I forgot the password AND username that I chose. How can I reset them?
This question seems promising, but it didn't work for me.
When I tried exec sp_password @new='changeme', @loginame='sa' as a query, I received:
Msg 15151, Level 16, State 1, Line 1
Cannot alter the login 'sa', because it does not exist or you do not have permission.
If you don't have other SysAdmin privilege login - you have nothing but reinstall it. Otherwise use it to change password.
Login as a Local or Domain Admins and just try to connect using "Windows Authentication".
Try following the instructions from this blog post entitled Disaster Recovery: What to do when the SA account password is lost in SQL Server 2005. It applies to SQL Server 2005, but should probably work with SQL Server 2008 as well.
You need to start SQL Server in single user mode using the -m command line switch. When SQL Server has started, a Windows administrator can connect to SQL Server using Windows authentication. You can then reset the password of the sa user. Make sure to restart SQL Server without the -m command line parameter afterwards.
MS SQL Server Password Unlocker helps to reset sa password saved in master.mdf! I had forgotten the sa password last week, and I fortunately found the MS SQL Server Password Unlocker at a password recovery blog. There are many password recovery solutions including SQL password recovery.