These are the simple steps by using which you can ste you SQL server sa password, mke sure you are an admin of the system.
- SQL server configuration manager
- Select SQL Server Services
- Select SQL Server(SQLEXPRESS) or any instance.
- Stop services.
- Properties > Startup Parameters > -m > Add
- Restart Services now.
- GO to ssms
- Select Server > Login through Windows Authentication.
- Go to Security > Change Now sa Password.
- Again go to Configuration manager remove -m from startup parameter
- Now login with sa password. :-)