For getting lock details, do the following
steps.

i)

select * from v$session
where sid
in
(select sid from v$lock
where id1 in
(select object_id from all_objects
where
object_name = <"name of the object against the query
was fired">))

This will give the info. about the lock.

ii) Either u can kill the session by connecting as SYS or internal.

iii) Otherwise u can get the process id by using the
ps -ef | grep (for ur process) , then
try to kill the process in the command line.

** Before doing that put a query in oracle between
v$session and v$process to know about the
magnitude of the process.
the