ok here it goes.. my xbox will play some games but won't even recognize that some are even in the tray or will say disc is unreadable when all of my games work perfectly fine on my freinds xbox..? and on black ops it won't let me play kin der toten, five, or arcade zombies.. but i paid for n downloaded the brand new map pack with land of the dead n that works fine? n when on live it won't let me play one map it just bakks me out? i forget the name of the map tho.. and now when i turn on my xbox 360 it doesn't even show that my profile is there!?? whats happening?????