trying to remove postgresql all together to start fresh, but stuck:

root@server7 [~]# rpm -qa |grep postgresql
postgresql84-server-8.4.5-1.el5_5.1

root@server7 [~]# rpm -e postgresql84-server-8.4.5-1.el5_5.1
error reading information on service postgresql: No such file or directory
error: %preun(postgresql84-server-8.4.5-1.el5_5.1.x86_64) scriptlet failed, exit status 1
root@server7 [~]# rpm -e postgresql84-server-8.4.5-1.el5_5.1 --force
rpm: only installation, upgrading, rmsource and rmspec may be forced

root@server7 [~]# rpm -e postgresql84-server-8.4.5-1.el5_5.1 --force
rpm: only installation, upgrading, rmsource and rmspec may be forced

1. Make sure there are no running PostgreSQL processes.
2. Try whether the following works for you: