Sounds buggered mate, I suggest you keep your old Hard Drive nice and safe, call customer support, if you are within warrenty then all fine and good, if not you may have to pay £120 for a new on (If they can't fix it).
You can keep all your save games because it sounds like your Hard Drive is fine ;)
-When mine went it was the Hard Drive and the Blu Ray Drive at the same time, on Christmas day no less!









