Using SQL Server Configuration Manager
How to view and start the Database Engine by using SQL Server Configuration Manager (installed on SQL Server)
Click Start, point to All Programs, point to Microsoft SQL Server, point to Configuration Tools, and then click SQL Server Configuration Manager.
If you do not have these entries on the Start menu, SQL Server is not correctly installed. Run Setup to install the SQL Server Database Engine.
In SQL Server Configuration Manager, on the left pane, click SQL Server Services. The right pane lists several services that are related to SQL Server. If the Database Engine is installed, the Database Engine service is listed as SQL Server (MSSQLSERVER) if it is the default instance; or SQL Server (<instance_name>), if the Database Engine is installed as a named instance. Unless the instance name is changed, SQL Server Express installs as a named instance with the name SQLEXPRESS. A green triangle icon indicates that the Database Engine is running. A red square icon indicates that the Database Engine is stopped.
To start the Database Engine, in the right pane, right-click the Database Engine, and then click Start.