SQL server is not starting in SQL 2012

Problem: The SQL Server (SQL2012) service failed to start due to the following error:
The service did not start due to a logon failure.

Solution:

Reference: http://support2.microsoft.com/kb/282254

To correct the password in Microsoft Windows 2000 Server and Microsoft Windows XP:

1. Click Start, point to Settings, and then click Control Panel.
2. Double-click Administrative Tools, and then double-click Services.
3. Use one of the following steps based on your instance type:
   • For a default instance of SQL Server, double-click MSSQLServer, and then click the Log On tab.
   • For a named instance of SQL Server, double-click MSSQL$YourInstanceName, and then click the Log On tab. Replace YourInstanceName with the actual name of the SQL Server instance.
   • For a default instance of SQL Server Agent, double-click SQLAgent, and then click the Log On tab.
   • For a named instance of SQL Server Agent, double-click SQLAgent$YourInstanceName, and then click the Log Ontab. Replace YourInstanceName with the actual name of the SQL Server instance.
4. Type the correct password in the Password and Confirm password textbox, and then click OK.

To correct the password in Microsoft Windows NT 4.0:

1. Click Start, point to Settings, and then click Control Panel.
2. Use one of the following steps based on your instance type:
   • For a default instance of SQL Server, double-click MSSQLServer, and then click the Log On tab.
   • For a named instance of SQL Server, double-click MSSQL$YourInstanceName, and then click the Log On tab. Replace YourInstanceName with the actual name of the SQL Server instance.
   • For a default instance of SQL Server Agent, double-click SQLAgent, and then click the Log On tab.
   • For a named instance of SQL Server Agent, double-click SQLAgent$YourInstanceName, and then click the Log Ontab. Replace YourInstanceName with the actual name of the SQL Server instance.
3. Type the correct password in the Password and Confirm password textbox, and then click OK.

NOTE: Changing the password through the Services applet allows SQL Server to start successfully; however, if Microsoft Search (Full-Text Service) is installed, it requires a subsequent password change through SQL Enterprise Manager (SEM).

Note If you are using SQL Server 2005, see the "Changing passwords and user accounts" topic in SQL Server 2005 Books Online

If it is on your Local machine, I rather choose the 'Log on As'  'Local System Account'