So, do as instructed! (as you aren't going to read the documentation).
- connect as SYS as SYSDBA
c:\temp>sqlplus sys/syspassword as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Sri Stu 4 21:27:53 2009
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL>
- unlock the account which is now locked
SQL> connect mike/lion
ERROR:
ORA-28000: the account is locked
Warning: You are no longer connected to ORACLE.
SQL>
SQL> connect sys/syspassword as sysdba
Connected.
SQL> alter user mike account unlock;
User altered.
SQL> connect mike/lion
Connected.
SQL>