All of you Windows users must be familiar with "Windows Rot" where an OS becomes slow and unstable after frequent install/uninstall of applications. To get rid of this problem, the best way is to install a Fresh copy of windows again.
Well to make it a bit easier, Microsoft could be bringing a new Re-install feature with its Upcoming Windows 8. Some leaked presentation slides show that the windows 8 will have a recovery option to "reset windows" while keeping all you personal data safe and also the option of reinstalling all of the app purchases from the Microsoft App Store.
