Total System Global Area 1309743464 bytes
Fixed Size                   452968 bytes
Variable Size             503316480 bytes
Database Buffers          805306368 bytes
Redo Buffers                 667648 bytes
ORA-01102: cannot mount database in EXCLUSIVE mode

SQL>
SQL>
SQL>
SQL> select open_mode from v$database;
select open_mode from v$database
                      *
ERROR at line 1:
ORA-01507: database not mounted

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01507: database not mounted
------------------------------------------------------------------------
Please help me

01102, 00000, "cannot mount database in EXCLUSIVE mode"
// *Cause:  Some other instance has the database mounted exclusive or
shared.
// *Action: Shutdown other instance or mount in a compatible mode.

You neglected to post the WHOLE session; like starting BEFORE you issued
the sqlplus command. What happens if you:

SQL> SHUTDOWN ABORT
SQL> startup mount
pfile='/oracle/app/oracle9i/product/9.2.0/dbs/initTHRBTE.ora'

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