Sony cybershot 4.1 megapixels mpegmovie vx dsc-s90

Question

When i turn on my camera it says access and then it tells me to turn the camera off and then back on but after i do this the same thing happens what could be the problem and how can i go about fixing this? 

The word 'Access' flashes on the screen for a split second and a fraction of the tone you hear when you turn on your camera is audible.  The screen remains blank and the camera does not turn on when in picture mode.  the camera does, however turn on when it is in playback mode.  'No file in this folder' is the message that is displayed on a blue screen.  Any fix ideas? (Sony DSC-P73 4.1 Megapixels).  I've tried replacing the batteries and taking out and re-inserting the MemoryStick.