A little something about everything

If you did not set the ..

Full Error:

'Agent XPs' component is turned off as part of the security configuration for this server. A system administrator can enable the use of 'Agent XPs' by using sp_configure. For more information about enabling 'Agent XPs' see "Surface Area Configuration" in SQL Server Books Online. (Object Explorer)

Fix Options:

1. if using GUI open services, locate SQL Server Agent, double click and set startup type to automatic then click start.
2. if you prefer to use command line you can just do the following on the master database:

   EXEC sp_configure 'show advanced', 1; 
    RECONFIGURE; 
    EXEC sp_configure 'allow updates', 0; 
    RECONFIGURE; 
    EXEC sp_configure 'Agent XPs', 1; 
   RECONFIGURE; 
   GO