While your PS3 is off, Hold the power button down and keep holding it until the PS3 turns on and beeps once the once again then shuts down (about 30 - 40 seconds), Then do the same thing again but release the button when you hear a double beep, This should bring you into a Safe Mode, From that go to [Rebuild Database] it will then reinstall all the device drivers for your PS3, This method should work if not then your drive is stuffed.