Did you send the cables with the system for repair too or just the system?
Is the TV a HDtv or a TV with component inputs?
If its not hooked up correctly it wont power up, just blink red.
Any type of sound or Pic from the TV before it shuts down?
Have you pushed the cables in tight?
Any type of note from MS saying what they did?
Try turning it on without the HDD?
Try playing it on a regular TV?
I would also like to know:
Would they give me a new headset, a couple of days after I got it I dont hear people and cant speak, I have to wiggle it around and it makes static, but thats it.