Harddrive isn't in BIOS, but when I can read it from a Linux Distro

So, my husband's computer has two drives (OS(disc) & Data(ssd)) and when he turned his computer on, it gave him a message like "This is not a boot disk. Please insert a boot disk" (or something).

I went into BIOS and the only drive that appears is the Data drive. My first thought was that his OS drive died so I was going to re-install the OS on the Data drive, but I wanted to back up files first. So I through a Linux distro on a USB stick and booted it up, but I noticed that it is seeing the OS drive in the available drives. Sure enough, I can access it (Read and Write) which is fantastic, but I'm curious...

How can the Linux OS see the drive when BIOS can't? Is the drive toast? If the Windows installer see's the OS drive, should I try to use it, or is it too unreliable at this point?

Please advise!

Submitted October 30, 2017 at 03:26AM by munin81 http://ift.tt/2zYryNq