Upgrading from 7.2 to 7.4.1 on Redhat 7

Hi,

I have owned a server for about a year, and apparently PostgreSQL 7.2 was
originally installed with Redhat.  I made an attempt to set up a database on
the current Postgres setup, but when trying to set up my configure files in
WHM (Cpanel) I received the error:

Setting up Postgres Config...Done
Reloading Postgres...pg_ctl: cannot find /var/lib/pgsql/data/postmaster.pid

And when I tried to set up a database or user from Cpanel, it just wouldn't
work.  There wasn't an error, but when I would add a user or database, it
wouldn't show up afterwords in my list of users and DBs.

So I did some research, and found out about running postmaster in a non-root
account.  I tried that and recieved this error message:

FATAL:  The data directory was initialized by PostgreSQL version 7.2, which
is not compatible with this version 7.3.3.

From that I figured that I must need to update to a more current version of
PostgreSQL.  I downloaded the .tar.gz for 7.4.1 and followed the
instructions, and installed it in  my usr/local folder.  Everything seemed
to compile correctly.  I didn't set the "--prefix=PREFIX" command line
option, so I assumed it would overwrite all of the files in the
/usr/local/pgsql folder.  The problem is, that there is no proof that I now
have an updated version of PostgreSQL.  When I try to use postmaster, I
continue to get the same result.

I don't know if this is enough information for anyone to be able to help me
figure out what is wrong.  If not, please let me know what else would be
needed as I would really like to get this installed and get working on the
database.

Thanks so much,
Jeremy