Xbox 360 unreadable disc problem?

My xbox 360 cant read discs properly. My gears of war 2 and cod waw say unreadable disc but there both almost brand new a few months old(tried at friends worked flawlessly). i called xbox my warranty ran out and i have to pay to get it fixed (why M$ are money hoggin basterds). If i buy a brand new 1 and switch it will it work or should i try purposely getting red rings? No immature, nonsence answers please.