PG 7.3.3 startup problem

I've installed postgres 7.3.3 on one of my debian machines.  On other
installations postgres is started automatically on machine bootup.
 However, on one installation it fails to do so.  In fact, it doesn't
appear that PG tries to start at all durring the bootup process.  I'm
still relatively new to linux, but from my understanding, I need to be
looking in the /etc/init.d directory for boot setup information.  Does
anyone know of a good reference I could learn more about how the linux
bootup process works, and how to trouble shoot this particular problem?
 Thanks in advance for the help

Kris