Quick post on what seems a common issue.
You apply SP1, reboot the server, and open Central Admin to see all the bright shiny bits in SP1.
But alas, Central Admin returns a 503 error. In services.msc you find most of the SharePoint services are not started – admin, timer, user code host, search. Oh no!
Fear not, it’s just a case of being too keen for the shiny. The last step of the upgrade is to run the SharePoint Config Wizard. This completes the upgrade process, starts your services, and brings you all that is shiny and new.