Here is the basic procedure:
Open regedit.exe (usually performed via the Run command).
Navigate to this key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
\Policies\Ratings
Right-click the key and delete it.
Open Internet Explorer and navigate to Tools | Internet Options | Content.
Disable Content Advisor. (Enter a new, more easily remembered password if you want.)
This simple Windows Registry hack will disable the Internet Explorer Content advisor and return Internet Explorer to its default state.