CONN / AS SYSOPER in Windows XP

I was running Oracle on Windows XP and found I could not do CONN / AS SYSOPER:

C:\>sqlplus /nolog

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Feb 11 23:44:21 2011

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL> conn / as sysoper
ERROR:
ORA-01031: insufficient privileges

SQL>

I went to the Oracle 10 client software under All Programs and found the Administration Assistant for Windows under Configuration and Migration Tools (click to enlarge it and bring it into focus):

I expanded it out as shown below and highlighted OS Database Operators - Computer:

I clicked on Action then Add/Remove:

This displayed the screen below:

I clicked the pull down arrow to the right of the Domain: box and selected the only choice displayed. This populated the Name / Description box:

I wanted to CONN / AS SYSOPER from user Andrew so I highlighted it and then I could click on the Add button:

Which added Andrew to the OS Database Operators - Computer box at the bottom:

So I clicked OK then I was able to do CONN / AS SYSOPER. When you do this, you log on as the PUBLIC user:

C:\>sqlplus / as sysoper

SQL*Plus: Release 10.2.0.1.0 - Production on Sat Feb 12 19:34:57 2011

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> show user
USER is "PUBLIC"
SQL>