How to: Restart the SQL Server Agent Service (SQL Server Management Studio)
SQL Server Agent can be stopped and started quickly from SQL Server Management Studio.
To restart the SQL Server Agent service
In Object Explorer, right-click SQL Server Agent, and then click Restart.
A message box asks whether you are sure you want to restart the SQL Server Agent service.
Click Yes.
A green arrow on the icon next to the SQL Server Agent node indicates that the service restarted successfully.