strange,
Read the entire post before comitting to anything stupid!!!!!!!
Shutting down from overheat should not cause any problems with files, except maby if you where saving at that time.
But in that case it shoudl still display and simply be unable to load and give a corrupt file error.
So best gues for this one is that the save folder somehow changed.
So either the map holding the save files has changed name or little buster suddenly decided it had to save to a different location.
A way to check this would be to open the map holding the save files vor little busters.
Then open little busters start a new game and save the game.
Take a look in the map holding the save files and check if any new files have been created or modified. (to make this as easy as possible sort by date modified) (also it may be necisary to reload the map with save games for correct display)
If a new file has been created or if an old file has been modified after you saved little busters then the problem lies with the save files themselves. (basically your are most likely fucked)
If no new file has been created and no file has been modified that the problem lies in the save location and you need to find the new save location.
Alternativly there may be a problem in the read and write permissions that the little busters exe has been given by your pc.
If it does not have permission to read the save files it will most likely say there are none.
And if it does not have write permission it cant write a new file or modifie an old one
In this case try running the little busters exe in administrator mode.
But first you should try a system restore to set it back before you could no longer acces your saved games.
this cant harm because you can revert it back if it does not work and generally a windows pc makes one almost every day.
So try setting it back about 24H before the problem started.
Hope this helps and let me hear the results