If you look on the net 4getmenot for cures you will prob see videos of people wrapping up there xboxes in towels and leaving it on. These are only temporary cures.
Theres 3 main things that can go wrong with your xbox..
1, The cd tray
2, The processor
3. Graphics chip
When you ring up xbox they will ask for a WINDOWS LIVE ID which they will use as security if you ever ring up to ask about anything else/to discuss your prob.
So basicly you defo need to ring X box Customer services, register the xbox in your name, with a Live ID and the console number. They then will send UPS out to pick up the x box and they ship it off to germany to be repaired.
If your xbox is chipped though i wouldnt bother, they will just send it straight back to you broken.
Hope this helps.