xbox makes screen roll.. any advice?

Hey,
I have a question... has anyone here ever came across an xbox that makes the television screen roll? I figured it might just be the cables or a loose wire going into the tv itself.. but then I hook a second xbox up to the same hook-ups and everything is just fine. Then I hood mine back up... and it continues to roll. Anyone have a clue as to whats wrong with it? Any advice would be nice

Later

 

are the two xbox's you have from the same region (NTSC or PAL)

 

both are ntsc... is there any way i could have switch from one or another and made it do this...