Microsoft Xbox 360 Console "static sound dots" Questions

...sound works but the screen is a grey static that changes with the different parts of the boot up. I know its not the AV cable or the TV because I hooked up my brothers xbox to the same set up and it ...

...sound daft but have you connected the cable properly from the logic board to the laser. i once forgot to connect this and it did the exact same thing. the laser might be dead too which can cause the ...