Windows 8 has the built in feature called „File History“.
It's intended use, as the name let one assume, is to store a revision history of documents. So if a mistake happens during editing files, the user can restore a previous version.
It's not a Backup
What it is not ment to be, is a backup service, which can restore the files on a new PC, e.g. in the case of a damaged or stolen PC.
This software restores the files from an external hard drive onto any computer running windows. Since the folder structure of the file history is the same as of the origin (with some restrictions), and all the files just get a date-time-suffix in their filenames, this tool just keeps the most recent version of them.
With Windows it is not possible to restore the most recent state onto any computer.
In case of a demage or a stolen notebook, you cannot use your backed up files.