一下转自http://www.cnblogs.com/yjhrem/articles/2340149.html
运行cmd命令行
录入 sqlplus /nolog 无用户名登录
conn /as sysdba 连接到数据本地数据
alter user system identified by password; 修改System 密码 为password
D:oracleora92in>sqlplus /nolog
SQL*Plus: Release 9.2.0.1.0 - Production on 星期四 8月 16 11:32:22 2007
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> conn /as sysdba 已连接。 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> alter user system identified by manger;
解锁方法 alter user system account unlock;
这样密码修改成功了