It depends on what you want to back up. Do you just want to backup your registry? You can export the entire registry, but you may have problems importing system critical registry entries later. The same theory goes behind the backup tool. Some files won't be copies because they are being used by system processes. I feel that the best thing you should do is use ghost. This way you can create a compressed image of your entire computer's state and it fires an image of the computer will it's not in the GUI of the OS so it will image everything.