Report ORA-12514 once restart Oracle 10.2 database

Question

OS: Windows2003 Standard Edition SP1
Oralce 10.2.0.1.0 for Micorsoft Windows(32bit)
I install Oracle 10.2 on Windows 2003, during installation, reports a waring at Product-Specific Prerequisite Checks:
Checking Network Configuration requirements ...Check complete. The overall result of this check is: Failed <<<<
Problem: The install has detected that the primary IP address of the system is DHCP-assigned.
Recommendation: Oracle supports installations on systems with DHCP-assigned IP addresses; However, before you can do this, you must configure the Microsoft LoopBack Adapter to be the primary network adapter on the system. See the Installation Guide for more details on installing the software on systems configured with DHCP.
I try to modify the Network config from assign IP address automatically to specify static IP address. then, Oralce can be installed successfully, and create database, connect to database... all work well.
But once I do restart(stop/start) the database server, then the database can not be connected and report error ORA-12514. but I do not do any changes, only restart the database server.
I also try to configure LoopBack metioned in the warning message, but it does not work as well.
I try to install Oracle10.2 on other clean machines with different OS, like Windows XP sp2, I got the same result.
Also, I doubt database server does not really start when restarting it, although no error or warning is reported. because of I watch the system memory usage, I do not see any increase of memory when I start the database server, it's not normal.
I setup a Oralce10.1 server on the same machine, it has not this problem.
Could anyone help me to solve it?
Thanks verfy much.
Frank
below is my sqlnet.ora, listener.ora and tnsnames.ora .
# sqlnet.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.
# 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)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
# listener.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = C:\oracle\product\10.2.0\db_1)
(PROGRAM = extproc)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
(ADDRESS = (PROTOCOL = TCP)(HOST = cnpb-dbserver5)(PORT = 1521))
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
ORA102EN =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = cnpb-dbserver5)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = ora102en)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
------------------------------------------------------------------

Answer 1

Paste the results of tnsping ora102en, hope it's useful to find any clue.
C:\Documents and Settings\Administrator>tnsping ora102en
TNS Ping Utility for 32-bit Windows: Version 10.2.0.1.0 - Production on 13-JUL-2
006 14:24:40
Copyright (c) 1997, 2005, Oracle. All rights reserved.
Used parameter files:
C:\oracle\product\10.2.0\db_1\network\admin\sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = cnpb-dbs
erver5)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ora10
2en)))
OK (30 msec)