deadlock detection

HI ,

We are currenlty using postgresql 7.2.1 database. But it does not
seem to detect deadlocks .
Suppose if a record is locked with update command and another
concurrent user tries to lock the same record and the first transaction
for some reason , eg. m/c hangings is not committed both the
transactions remains locked for indefinite period . I have checked the
setting in postgresql.config for deadlock_timeout which is set to 1000
. Than why doesn't the transaction deatect deadlock after 1000
millisecond .
Secondly if the frontend process is killed but due to some reason the
backend postgres process remains , than how can it be terminated .For
if i try to use kill command all the postgres processes gets
terminated .
Please help

--
Regards,
Shobha