>Is there a way to prevent registration of file types in explorer? Many extensions are common to different applications (VFP and PCAnywhere is an example), so double-click on an .scx may generate an error if that file is a PCAnywhere file registered as a VFP file.

You can delete the file association for a given file extension by deleting the registry key hierarchy at HKEY_CLASSES_ROOT\file extension; for example, to keep .DBF from having default actions associated with them, you'd delete HKEY_CLASSES_ROOT\.dbf