But, sometimes, the files/folders are left behind, and therefore, the guide tells you to remove these, in case they are left behind, and interfere with the installation next time.
Usually, the uninstall should remove all files/folders.
The guide clearly states that first you have to uninstall iTunes from the Control Panel, and after the uninstall is done, then you have to delete the files/folders of iTunes, which are not removed after uninstall.
Superfrog25, the uninstall/repair should have been done before you deleted the files/folders in Program Files.
