Using Office 2007 on Windows XP. I tried to open a doc file and got the warning: This error occurs if you try to open a Microsoft Office document and the file type for that document has been blocked by a registry policy setting. To help secure your computer, Microsoft or the administrator of this computer implemented a registry policy setting that prevents opening this type of file. I followed the yellow-brick road to 922849 which says: Locate and then click the following registry subkey: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Word\Security\FileOpenBlock I diligently searched but could find only the one category "Systemcertificates" under "Microsoft". What am I doing wrong?