If any of them have stopped saving, which are they.?
I have found recently that my pokemon crystal version has lost its save due to the battery going flat, thereby joining my pokemon gold version which went flat ages ago (though for some reason my silver version is still fine, probably cause it was the one I played the most), though my pokemon yellow version is going fine (mostly beause unlike gold silver and crystal, it doesnt need to use extra battery to keep the clock going).
ETA: question marks.
