Hi and welcome.
Shutdown is usually achived using commands such as shutdown or poweroff as root. These commands usually point to /sbin/halt so you could alternatively use command such as
instead of poweroff.
If the shutdown sequence stops before the end (such as with message "powering down...") then you need to configure your power management. Two most used solutions are APM (advanced power management) and it's successor ACPI (advanced configuration and power interface). I myself prefer apm since it seems more basic and simplier for me. You could try modifing your /etc/rc.d/rc.modules (actually I have no idea what startup system Fedora uses so it might not be there) and uncomment the # before apm. That will load apm every time the computer starts. If you'd like to activate apm right away, you should use the command
Also use the command "man" to find out more about stuff. For example in that case both
would be useful to you.
I'm not behind my Linux box right now and I'm rather new myself so there might be some mistakes or inconsitencies, if there are, let me know. Someone else will probably explain you more, this is what I know.
fakeedit: Well chrism01 basically already explained everything : D