Open Unknown Files with Notepad in Windows XP

It is possible to associate an application with files of an unknown type in Windows with the following instructions by configuring the registry:

1. Start the registry editor by clicking on the Start menu -> Run -> Type in regedit.exe -> Click OK
2. Navigate to HKEY_CLASSES_ROOT\Unknown\shell
3. Right-click the folder and select New -> Key
4. Enter the name "openas" and press Enter (don't type the quotes)
5. Select the new "command" key, right-click it and select New -> Key (don't type the quotes)
6. Double-click the "Default" value
7. Change the name of the application, for example "NOTEPAD.EXE %1" for the notepad. "%1" is needed to pass the document name to the application.
8. Click OK