Postgres startup problem

Hi all,
I have a problem starting the postgres database.
I am using postgres 7.0.2 on a Redhat Linux 6.2. I had to shutdown my computer
since it was hanging. I have the postgres start command added to the bootup
process. I have rebooted the Linux machine several times and it was starting
postgres correctly. But this time it was saying "Postmaster could not connect to
unix socket 5432" . I checked if any other instance of Postmaster was running by
checking the process ids. There was no second instance running. Also, I tried to
stop and restart postgres using
"/etc/rc.d/init.d/postgres stop" and "/etc/rc.d/init.d/postgres start" commands.
It was saying
"Starting Postres [ ]". If Postgres was really started it will show the process
id within the square brackets. But this time it did not show the process id. If I
try to connect to the database using psql it gives the error message "Postgres
could not be connected to socket 5432".

Please let me know if there is a different way of starting  postgres.
Thanks,
Nataraj