You probably lost the "global" file in the save folder during this incident. The global is responsible for telling the game that save files exist, and that to show in the preview in the loading screen. If the file doesn't exist, the game thinks there is no save, which is why the load option was grey and not usable for you.
Most all old save files out of the save folder first, then start the game and create saves in all save slot in which you previously had saves. (The save files have the number for the slot to which they belong.) Afterwards overwrite the new save files with the old save files which you moved out of the folder earlier. The preview will be wrong until you load and re-save into that slot again, but the progress should still be your old.