WAIT!
Don't reformat it or repartition it yet. I have had this happen multiple times with some of my machines and, long story short, you are at the mercy of Windows
. 9 times out of 10, it's nearly impossible to fully fix it. However, we have some very high dollar forensics software here in the studio that will retrieve the photos and/or files that you need to get off of it. If you want, let me know and I'll upload a copy for you to get some of the files off of the corrupt drive.