our one here in the house was sent back, its my housemates one.
He brought it back to the shop it was bought in and it was then sent on to sony to sort out.
the problem happened because the machine was switched off at the back while the power was still on (ie the green light). This corrupts the hard drive and screws it over.
Its like you know the way your saving something or downloading something on it and it says do not turn off the power, well could this have happened?? its something to do with the high def i think and that it uses so much space or something.