In 2.7, turtledemo is in <pythondir>/Demo/turtle when those directories are present. They are not currently installed by the 2.7 Windows installer, but this could be requested (of Steve Dower) on another issue. A 2.7 patch would be slightly tricker as it would have to check for the existence of turtledemo. Options:
* check before installing the menu entry and dont add it if not present.
* always make menu entry and check when clicked.
Is turtledemo present on *nix/mac often enough to make a 2.7 addition worthwhile even without Windows?