I have developed a windows service using visual studio 2008 and .net fw 3.5.1 I set the StartType of the service installer to Automatic. When I install the service in a Windows Server 2003 the service appears with the StartType set to Automatic. So far so good, but... when the server is restarted the service doesn't. What might be happening?
Troubleshooting 101: does the service run in manual mode? It sounds as if the Service itself doesn't run. Check your event log for entries.
If the Service can run in manual mode, only then do you look to the server for startup issues.
Edit: if the service can run in manual mode, consider the other controllable aspects of the service, such as the account under which the service executes (LocalSystem or some other account?) Other things to look at are dependencies you service has on other parts of the server. Does it require other services from the server to be enabled when it initializes?
What does the service do? It might fail to start because the service itself doesn't run (as stated by jro). It could also be that your service isn't starting because it depends on another service which is not yet up and running during startup. If the latter is the case you should define a service dependency. That will delay the start of your service until the dependency has been started.
To analyse the problem, have a look at the event look. Hopefully you will find some more information there.