As you may or may not know, Windows 8 will be out soon and people are already testing out pre release versions to see all the new features. One exciting feature is that Windows 8 will let you reinstall Windows while keeping your files intact. There will be a new "refresh" option that will restore your PC back to a clean state while keeping all of your data and settings intact. This process will be completely automated so you wont need to back up your files or settings beforehand. This option will preserve your Metro applications, but not your regular desktop programs because a desktop app could be the cause of the problem requiring the reinstall.
There will also be the "reset" option that will securely remove everything from your computer including programs, settings and all data and then reinstall Windows. This will come in handy if you plan on giving the computer away or selling it and want to make sure all of your information is removed from the computer first.