Have used my WD My Book 1Tb external drive successful for 18mths to backup PC (Widows 7). Now it won’t let me access it to view folders/data, nor do the unit’s lights show any data content being stored. I’m frequently getting a pop-up Windows message asking if I want to Format drive G:… as there’s no patition. When I restart it, it lights up and I can feel the disk spinning, but the lights just keep flashing. Very frustrating, please help! It has all our family photos stored on it!