After making your changes, reboot the system. If you notice that anything isn't working properly, start the registry editor again and choose Import Registry File from the Registry tab at the top. Find the backup you made earlier and import it. Now reboot and everything should be as it was before. I hope that by trying out the the guides, you have a smoother running computer and have learned a few things.
Computers are marvelous tools and the limit to thier functionality is nowhere in sight.
Because of this facility, their complexity is practically infinite. If you have questions, don't hesitate to ask . I'll answer what I can and lookup what I cannot.