A rather strange moment to convert from Windows 7 to Windows 10.
I expect the hard drive doesn't show up if you boot in Linux (their partition manager is called GPEDIT) either. And I expect it doesn't show up in Windows 7 either; not if you go back to your latest image, and not if you do a clean install of Windows 7 (after which reinstalling Windows 10 is free). But since all of this is free to try, just try.
If no luck, put that drive in an external enclosure. Might work. If still no luck, it's time for a new hard drive. Copy your files from your backup to it.
My extra hard drive is not showing up in disk management or any where else.
I was working just fine before i upgraded to windows 10 i was using windows 7 before. I don't know what to do the SATA cables are fine i checked them and they work. Anyone have a idea?