Dude, that sucks Majik.[:' (]
(Completely off-topic, but nice TV
) Like Quez said, go play it W/O the hard drive, and if your problem is solved then you' re out 100 bucks, and you can ignore the rest of this. However if it gets no better, go out, spend the 8 pounds and get yourself a Datel Data-Transfer Kit or something of that ilk, I dunno if Datel does business in the UK.
But offload your files onto a PC, and send in your hard-drive + console. Worse comes to worse, the whole lot is botched and they send you a new one, and you' ve still got your HDD data. Best of luck man, and oh, by the way, just to get you in the mood for the Microsoft representative:
" Is the console plugged into an outlet?"
" Does the console have a cable running from your TV to your 360"
" Was the console
on when you noticed the problem?"