Oracle密码丢失办法

接着刚才的日志说，刚把服务找回来，可我根本不记得任何账号密码了，汗，这么搞吧

C:\Documents and Settings\lidongbo>sqlplus /nolog

SQL*Plus: Release 10.2.0.3.0 - Production on 星期六 3月 5 22:23:04 2011

Copyright (c) 1982, 2006, Oracle. All Rights Reserved.

SQL> conn /as sysdba
已连接到空闲例程。
SQL> SELECT host_name, instance_name, version FROM v$instanc;
SELECT host_name, instance_name, version FROM v$instanc
*
第 1 行出现错误:
ORA-01034: ORACLE not available

SQL> alter user sys identified by sys;
alter user sys identified by sys
*
第 1 行出现错误:
ORA-01034: ORACLE not available

SQL> startup
ORACLE 例程已经启动。

Total System Global Area 612368384 bytes
Fixed Size 1292036 bytes
Variable Size 289409276 bytes
Database Buffers 314572800 bytes
Redo Buffers 7094272 bytes
数据库装载完毕。
数据库已经打开。
SQL> select * from dual;

D
-
X

SQL> alter user system identified by password;
用户已更改。
SQL> alter user sys identified by password;
用户已更改。
SQL> exit