Your right, the link given guides you to Microsoft online documentation on the Windows Shell in the Platforrm SDK, User Interface Services.
<a target="_blank" href=http://msdn.microsoft.com/library/default.asp?PP=/library/toc/psdk/user/user0-3-0.xml&tocPath=user0-3-0&URL=/library/psdk/shellcc/Shell/shell_intro.htm>http://msdn.microsoft.com/library/default.asp?PP=/library/toc/psdk/user/user0-3-0.xml&tocPath=user0-3-0&URL=/library/psdk/shellcc/Shell/shell_intro.htm</a>
Look for the chapter that tells you how to establish a new Name Space. Use this info to remove the ones you do not want to see.
You may have to hack the GUIDs / CLSIDs out of the registry.
Make sure you have a backup of the registry and ERDs in case you get in trouble.
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Regards - Richard