Ok, this might get complicated, but bear with me!
I got Assassins Creed today so I was playing that when all of a sudden the graphics went all funny coloured, and then went completely, my TV said there was no input. I still had audio, just no video.
Luckily I live with my brother and he has a 360, so I put my console on his TV and got the same thing. I tried it without a hard disk in and still no video output on either TV. But here's where it gets really complicated...
I put his console on my TV and it worked fine. Then I put my hard disk on his console, put it on my TV and there was no video output. But I've also put my hard disk into his console but on his TV, and it worked fine.
So to sum up..
My console + my HDD + my TV = no video.
My console + my HDD + brother's TV = no video.
Brother's console + my HDD + brother's TV = fine
brother's console + my HDD + my TV = no video
Brother's console + brother's HDD + my TV = fine
I'm completely baffled. I've phoned Microsoft and they're getting me a replacement for free (luckily I'm about 1 week inside my warranty) but what I don't want is for the replacement to come and have the same problems when it's hooked up to my HDD.
Anyone have any thoughts/ideas?