Go to run type services.msc
Right click on the SQL Server Agent (MSSQLSERVER)
Then check in the properties your startup type might be disabled change it to automatic or manual and try again it will enable the start option
Question
I want to start the SQL Server Agent (sql server 2008 R2 Enterprise edition), then I did:
but when I right click the start item is disable.
Solution
Go to run type services.msc
Right click on the SQL Server Agent (MSSQLSERVER)
Then check in the properties your startup type might be disabled change it to automatic or manual and try again it will enable the start option