My favorite game died... How!?

[Pokemaster Ash]

I was playing one of my favorite games, Mega Man Battle Network 2, earlier. In fact, I was playing it in the unlockable Hard Mode as a fun challenge and was making HUGE progress. Unfortunately today I mysteriously lost both save files, the regular game and the Hard Mode game. Dismayed, I restarted so I could get back to pwning the game, but...

I COULDN'T SAVE THE GAME!!!

It seems the save function's dead on my game, and I want to know how the hell it happened. The game was functioning PERFECTLY, and out of nowhere my save files are gone and I can't make a new one. Did the internal battery or whatever die? This was one of my all time favorite games, too...

EDIT: ....okay, my game just faked me out. I just checked again and BOTH files were back and fully intact. Okay, something weird just happened...