PostgreSQL stopped running and dont know how to fix it?

My PostgreSQL is in stopped mode. If I try and restart I get:

Failed to start service : Starting PostgreSQL 8.3 database server: mainError: could not exec /usr/lib/postgresql/8.3/bin/pg_ctl /usr/lib/postgresql/8.3/bin/pg_ctl start -D /var/lib/postgresql/8.3/main -l /var/log/postgresql/postgresql-8.3-main.log -s -o -c config_file="/etc/postgresql/8.3/main/postgresql.conf" : failed! failed!

Is there a way to remove and install to default state... none of my websites use this database but do have it enabled.? Thanks, JoelM