I am using an Asus computer with an external hard drive that was once used in my Sony Computer. When the computer went out about five years ago I removed the hard drive and bought a case for it, formatted it and stored many pictures and other information on the drive. It has worked fine for the last five years but today when I turned it on it failed to show up in My Computer. By the way, I am using Windows 10, which I might ad was a gigantic mistake taking the free upgrade, so my main intent after I get this drive to work is to save everything and restore this computer back to factory and Windows 7. After turning it on it failed to show up in my computer, the drive shows up as working properly in my device manager, however, going deeper into the problem I was able to find it in Disc Management and it shows as "unallocated", and there is no drive letter. I would like to save the information on the drive and find that there are several means of obtaining a drive letter without formatting and losing all of my information. However, I am unsure of exactly what to do and don't want to accidentally lose the data.