I have a GU501GM and my D drive has a blue question mark next to it. I cannot access it anymore and does not show up in disc management. I have been getting blue error screens the last few months, I don't know if that has anything to do with it. Before I got that question mark, it was working just fine. Windows said it needed an update and I updated and restarted it. It was after that I noticed it was gone. I have opened up the laptop and reseated everything, but no change. I have restarted it many times, no change. I have had this laptop for over 2 years now. If anyone know what I could try to fix it, please let me know! Thanks!