[Newbie]Redhat 7.3 and X doesn't start default

[newbie@XFree86.Org (Captain Ahab)]

I have Redhat 7.3, and instead of X coming up on boot automatically, it
brings up a text prompt.  This happens even though I've got the line:

id:5:initdefault:

in my /etc/inittab file.  I can start x with startx, but I'd rather have
GDM come up auto with X on boot up.  Please offer suggestions.  Thanks,

Ahab