Ok so, a friend's pc started being slow on windows 7, so I suggested if I install windows 10 on her computer, she said to not remove windows 7 though cause it had some stuff she needed on it, so I dual booted it, it has been working fine for a couple of months now and she always gets a list of both systems so she could choose whether she wants to go on windows 7 or 10, now she doesn't get that list and it seems like there isn't even windows 7 on it anymore, any help? I also changed the boot drive 3 times, there are 2 partitions i tried both and both didn't work, and I tried the hidden system partition that takes up like 200 Mbs, and it booted me to windows 10. What do I do?