There's a bit of info on this page:
How to Remove Content Advisor Password
in Internet Explorer
The following steps will remove any
password set in the Internet Explorer
Content Advisor and allow you to reset
the program to its original state.
1) Click on Start and choose Run.
2) Type in RegEdit and select OK.
3) Now click on the little plus sign
to the left of H_KEY_LOCAL_MACHINE.
4) Continue to drill down, always
clicking on the plus sign at the left
of the named key, through Software,
Microsoft, Windows, Current Version
5) Now click on the Ratings folder.
6) In the right pane of the RegEdit
window, you'll see an icon called Key.
Click on it and press Delete.
7) Next, choose Registry and then Exit
to exit RegEdit. You've just deleted
your original Content Advisor
8) Restart the computer and run
Internet Explorer again.
9) Choose View and then Internet
Options (or Options for version 3.x).
For IE 5 or greater, Click on Tools,
10) Click on the Content tab and click
on Disable. When asked for a password,
don't enter anything; just click on
OK. This will disable Content Advisor
because there's no longer a password.