Microsoft IE has a Content Advisor password which if forgotten, makes it impossible for anyone to access the sites screened out. These sites don't contain offensive material- they are simply unrated.

You can clear out the existing password by deleting the following value:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Ratings

There may also be a sub-key .default. If the file %systemroot%\System\Ratings.pol exists, delete it or rename it. Reboot. In Internet Explorer, go to Tools | Internet Options and click the Content tab. Click Enable Ratings and specify a new password.

Technet articles
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