Oracle Database Discussions

Dear All,
I am new to oracle and this forum. I installed Oracle 11g and Oracle forms in my system.
When i Try to connect to database thru SQL* Plus, am getting error as "ORA-12541- TNS:No Listener". Same issue when i try to connect thru Forms Builder. This is how my tnsnames.ora looks
# tnsnames.ora Network Configuration File: C:\DevSuiteHome_2\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = Pradeep-PC)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = PLSExtProc)
)
)

ORACLE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = oracle)
)
)

LISTENER_ORACLE =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))

ORACLR_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
)
(CONNECT_DATA =
(SID = CLRExtProc)
(PRESENTATION = RO)
)
)
Kindly guide me