Following the below steps:
Oracle account is locked
1. Type "Conn /as sysdba" in the sqlplus window;
2. Type "alter user AccountName unlocked. Try to logon again.
Oracle user account logon denied
1. Type "Conn /as sysdba" in the sqlplus window;
2. Type "alter user AccountName identified by NEWPASSWORD.
Oracle account is locked or oracle user account logon denied
原文：http://www.cnblogs.com/alexli2010/p/4793688.html