Why does Postgres refuse to start as service?

I try to install Postgres on Windows (Server 2003). Both versions I tried (8.3, 8.4) fail at the end of the installation because the service cannot be started. I tried with different users for the service without success.

Any ideas any开发者_如何学编程one?

---

It's usually a permissions issue. Check that the installer set up the permissions correctly for the user running the service (usually "postgres").