This registry hack is nothing new, it's been around forever… think of this as a refresher course. Also note that you can use this same technique to substitute any other application that you'd like by adjusting the path in the registry to point to the different editor.

Manual Registry Hack

Open regedit.exe through the start menu search or run box, and then browse down to the following key:

Code:
HKEY_CLASSES_ROOT\*\shell

Right-click on "shell" and choose to create a new key, calling it "Open with Notepad". Create a new key below that one called "command". Double-click on the (Default) value in the right-hand pane and enter in the following:

Code:
notepad.exe %1
The change should take effect immediately… just right-click on any file and you'll see the next menu entry.