SQL Server Express does not ship with SQL Server Agent. So, when you say that SQL Server Agent service is running, I am not sure whether it is for the SQL Server express instance.
Since the Express does not support the SQL Server Agent, there is no way of installing it (by the way, the Management Studio that you reinstalled is just a client-side component and will have no effect on what services your SQL Server instance provides). You can search the Internet for 3rd party scheduling tools, however, note that they would not be supported by Microsoft, and therefore should not be used in production environments.
commented on Feb 18 2012 2:04PM