Mine is the same!! A guy in a camera shop mentioned that it might be the image processor but if that is the case it is cheaper to buy a new camera!!  However I took mine back to the shop (without the receipt) and because it had developed a receipt they sent it back to be repaired.  Haven't had it back yet but hoping all will be fine when I do.  Read the consumer rights act - you are well within you rights to expect replacement or repair (though not a refund).
                 Lil
                
 September 2009