Hi,
first you must check where is this file:
postgresql-9.2
in *nix systems you can do it by using this:
find / -name postgresql-9.2
in my system it returned:
/etc/rc.d/init.d/postgresql-9.2
now to start/restart/stop postgres, just ran the next instruction using root:
/etc/rc.d/init.d/postgresql-9.2 start
/etc/rc.d/init.d/postgresql-9.2 stop
/etc/rc.d/init.d/postgresql-9.2 restart
To check what is going on with your DB, you must read the file postgresql-<year>-<month>-<day>.log located on the pg_log directory.