How can i reinstall the xbox 360 spring update. I've noticed that ever since I downloaded the spring update my console tends to lag after an hour or so of game play so I was trying to uninstall it and I thought it was possible because I heard somewhere that there was some kind of rollback feature so I went to memory and saw a new tab called system items and deleted everything in there but nothings change so im affraid that a probably screwed with something. How can I reinstall