blackroseivy
Blackroseivy, I so hope you've now bought a portable hard drive on which to back up all other data files on your computer. If the art files have "just" disappeared then you have a problem. Files can't just disappear but there might be an internal problem with the system that operates your computer (its OS) that corrupts files or loses them from the directory. Could even be that the files have become hidden in some way.
As I said, I was sure they were on a flash drive but they weren't when I checked. I do remember my sis having me give her everything I wanted saved from my old computer when the files definitely WERE there. I'm crossing my fingers.