Unfortunately, as you may have surmised from the resounding silence, there is not much you can do: if the periodic unsaved-file “backups” aren’t in their folder, then the crash caused Notepad++ to exit during the brief time that the files didn’t exist (or you didn’t have the unsaved-file backups option turned on)

For the future, I recommend saving your files to known locations frequently, rather than leaving them opened-and-unsaved. For more, see our backup FAQ