The thing is, is after a while Windows has been known to re-write itself over time and lord only knows why. Most of the time when it does that and you defrag and move everything around Windows has no idea what you did with it, or what it did with itself lol. Best idea usualy is to have most everything backed up periodicaly just in case something happens cause one of your files might have gotten infected then you backed that up ect. Im sure you know what im talking about. A usual format for performance reasons is a good idea.