I just got my XBOX360 about 2 weeks ago. I have not bought any games yet but I have rented Lost Planet, ESPN MBL 2K7 and Rainbow Six Vegas. I played all these games successfully but each one froze up on me at least once or said I need to "clean" disc. Granted these rentals games were not in the best conditions. Is this normal, or could my system be defective? I waited so long because I thought Microsoft fixed all issues.