oracle入门配置

oracle连接啥这么复杂啊.

oracle 10g
用ps/sql dev怎么也连不上.
用sqlplus可以登陆.net manager之前测试连接了成功的.现在搞得也连接不了.

listener.ora:

SID_LIST_LISTENER =
  (SID_LIST =
  (SID_DESC =
  (SID_NAME = PLSExtProc)
  (ORACLE_HOME = D:\oracle\program\10.2.0\db_1)
  (PROGRAM = extproc)
  )
  )

LISTENER =
  (DESCRIPTION_LIST =
  (DESCRIPTION =
  (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
  (ADDRESS = (PROTOCOL = TCP)(HOST = 20090604-1449)(PORT = 1521))
  )
  )

------------------------------------------------------------
tnsnames.ora:

FIRSTDB =
  (DESCRIPTION =
  (ADDRESS_LIST =
  (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 5555))
  (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 6666))
  )
  (CONNECT_DATA =
  (SERVER = DEDICATED)
  (SERVICE_NAME = FirstDB)
  )
  )

ORCL =
  (DESCRIPTION =
  (ADDRESS_LIST =
  (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
  )
  (CONNECT_DATA =
  (SERVER = DEDICATED)
  (SERVICE_NAME = orcl)
  )
  )