--1. Use Contol Panel Services to Start/Stop the SqlServerAgent Service

--2. Start and Stop Agent from DOS prompt
net start sqlserveragent
net stop  sqlserveragent

--3. Determine if SQLServerAgent service is started via Query Analyzer
exec master..xp_servicecontrol querystate, sqlserveragent

--4. Determine what services are started using SQLServerAgent as an example
create table #List(description  char(255))
go
insert into #List exec XP_CMDSHELL 'NET START'
go
select * from #List where description like '%SQLServerAgent%'

--5. Create a Stored Proc to turn on SQLServerAgent everytime SQL Server is started
create proc AutoAgent as
  exec xp_cmdshell 'NET START SQLSERVERAGENT'
go
sp_procoption AUTOAGENT, STARTUP, TRUE