I have a windows vista hp pavvilion a6137c desktop pc and the other day I was just doing what I've done casually for 3 years now is just surfin YouTube and what not. So after finishing up on the computer I decide to shut it down so I go and turn it off but I see the shutdown button has the "shutdown and install updates" alert so I hit it turn off the moniter and walk away. I come back the next morning and now when I Turn on the computer it reads "No bootable drives detected please insert proper media and reboot". I don't know all that much about computers so if anyone cam help me and be really specific on how to fix it it would be so deeply appreciated thank you.