I've seen a fair few Xbox 360s with corrupted video output, but I haven't seen it look quite like that before. Is that pattern moving across the screen like interference, or remaining still? (Obviously can't tell from a photo
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You say you've tried component - have you tried good old composite as well? Any luck with that?
Have you got a different TV you can try composite, component and/or HDMI on?
Also what about the sound - are you getting any audio at all? If you're not getting any through your TV then try some external speakers if you can, just to see if the signal is actually being outputted.
If I remember right (someone correct me if I'm wrong) you can reset the video settings by holding down the Right Trigger and the Y button on the controller and switching the 360 off then back on again. Not sure if that will help, but give it a shot.
If it's not your settings and you can rule out all your cables and TV then, yeah, it might be an overheating problem. In that case performing some sort of repair such as an X-Clamp replacement or reballing might fix it.