How do I get my maps back?

Hello. I have a very serious problem; all my maps that were in the maps folder (as well as in the contest maps folder) have suddenly disappeared. Only the original maps remain, and all my creations have simply vanished!:smile35: Also, all the folders I created have disappeared.:mad:

Added 7 minutes later
I found one of the maps and tried to open it in the editor, but it says that the file may have been deleted or moved!