Question: How can I turn a given normal application into a Windows service under Windows XP?

EDIT: This is a server application, so it has no GUI and does not require any input or output.

Answer: 
Also, once you successfully started your normal application as a service, I would suggest to test how the application behaves when you log off.

Some applications (old ones?) don't like receiving the message that is sent when logging of or shutting down the computer.
[FireDaemon](http://www.firedaemon.com/) is another option for doing this.