A month ago the hard drive that has all of my this year's raw photos on it seemed to die on me (Windows 10.) "Computer Management" suggested that it needed to be formatted, but I didn't want to do that until I could at least try to recover some of my files. I Googled for software that might do that and found a recommendation for Data Rescue 5 (available for Mac or PC.)
The nice thing about Data Rescue 5 is that you can download a free trial version which will scan your drive and show you a list of all files that it can recover, but it won't let you recover them. If you like the list, you can shell out $99 to get the working version.
I did, and it recovered all of my photos and most other files on that drive.
So I suggest you at least try the free download version to see if anything can be easily recovered. Or, if the drive isn't physically damaged, you might try a low-level format.