oracle ORA-27101 Shared memory realm does not exis

oracle 本来可以用，新建了个库后，新库不能用，我把它删了，原来的库ORCL用sqlplus ，plsql  以及用oralce 的net manager 测试都登录报错误，
ORA-27101 Shared memory realm does not exist
ORA-01034 ORACLE not available
怎样解决呀？
set ORACLE_SID=orcl  实例也重新设置了。服务，监听重新启动了！
CMD 中tnstping orcl 也可以成功。
-------------------------------
我的tnsnames.ora 文件也没看出什么问题
ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )
------------------------------------------------------------
listener.ora 文件

# listener.ora Network Configuration File: D:\oracle\product\10.1.0\Db_4\network\admin\listener.ora

# Generated by Oracle configuration tools.

SID_LIST_LISTENER =

  (SID_LIST =

    (SID_DESC =

      (SID_NAME = PLSExtProc)

      (ORACLE_HOME = D:\oracle\product\10.1.0\Db_4)

      (PROGRAM = extproc)

    )

 (SID_DESC =

       (GLOBAL_DBNAME = orcl)

       (ORACLE_HOME =  D:\oracle\product\10.1.0\Db_4) 

       (SID_NAME = orcl)

      )

   )

LISTENER =

  (DESCRIPTION_LIST =

    (DESCRIPTION =

      (ADDRESS_LIST =

        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))

      )

      (ADDRESS_LIST =

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

      )

    )

  )

------------------------------------------------------------------------------------
还有sqlnet.ora 文件
SQLNET.AUTHENTICATION_SERVICES= (NONE)

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

------------------------------------------------------------------


按网上说的，CMD 中 connect /as sysdba  结果报ORA-01031: insufficient privileges。