What do you see in SQL Server Configuration manager? Did you check SQL Server Agent Error log?

>
>I have a SQL Server Standard 2008 R2 instance running which was upgraded from the Express version. This is on a Windows Server 2008 R2 machine set up as a domain controller.
>
>I am now trying to implement some Replication (following the Stairways series on sqlservercentral.com http://www.sqlservercentral.com/articles/Stairway+Series/72274/) and am getting problems due to (I think) the SQL Server Agent not running.
>
>First confusion is that under services.msc it states that the SQL Server Agent is running, but inside SSMS the SQL Server Agent node has a little white x inside a red circle indicating that it is not running. If I try to start it inside SSMS I get a message:
>
>Unable to start service SQLAGENT$SQLEXPRESS on server < my server name >. (mscorlib)
>Additional Information:
>The SQLAGENT$SQLEXPRESS service on < my server name > started and then stopped. (ObjectExplorer)
>
>The SQL Server Agent is set to log on as "Network Service".
>
>I have found lots of stuff about this on-line but nothing seems to work, or I am getting lost in the quagmire of too much information. Any guidance would be welcome.