Oracle Database Discussions

Hi,

I am new to ORACLE database. I am using Oracle Database Express Edition 11g Release 2.
I installed in my local computer but i got following error when i am configured it. I am running windows 7 Home premium 64-bit operating systems. No firewall issue.

This is my error:

SQL*Plus: Release 11.2.0.2.0 Production on Sat Oct 8 23:03:31 2011

Copyright (c) 1982, 2010, Oracle. All rights reserved.

SQL> connect
Enter user-name: system
Enter password: xxxxxxxxx
ERROR:
ORA-12543: TNS:destination host unreachable


1. My listener.ora file :

SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = CLRExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
(PROGRAM = extproc)
)
)

LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
(ADDRESS = (PROTOCOL = TCP)(HOST = Thivakhar-PC)(PORT = 1521))
)
)

DEFAULT_SERVICE_LISTENER = (XE)



2. sqlnet.ora file -
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.

SQLNET.AUTHENTICATION_SERVICES = (NTS)

XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = Thivakhar-PC)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)

ORACLR_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = CLRExtProc)
(PRESENTATION = RO)
)
)


3. tnsnames.ora file -
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = Thivakhar-PC)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)

ORACLR_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = CLRExtProc)
(PRESENTATION = RO)
)
)



Please anyone help me to resolve this issue??