WTF ? My Xbox 360 or the Game's........?

most of my xbox 360 games dont work, but why ? i've had a 360 since they came out but have sold my old 360 and got a brand new 360 elite (not pre owed), the problem is most of my games do not work, the xbox doesn't even pick anything up i wouldn't mind if it said disc dirty or damaged i just keep getting open tray as if there was no game/disc in it, but they all worked on my older 1 ? i've spent a fair few quid on all my games to get them cleaned and all scratches removed but still no joy in the matter, i even brought a new game and that did the same thing, im thinking it's the xbox now as the games work great on a friends 360 which is my old 1 ? any help would be grateful before i get in touch Mr Bill Gates at Microsoft lol, peace and respect to all