Help with micro SDHC please

Hi there,

I should think this is a common problem but couldn't find existing threads.

Have a problem with a 2GB micro SDHC which is being used in a DSTT card.

I'm guessing that I over filled the SDHC card with roms because I now have a conflict. Now I can't access the games when I turn the DS on.

When I put the micro SDHC in my computer & try to access the files I am unable to & I am asked to reformat the card, although the properties confirm a full card.
If I reformat the card I will lose months worth of save files along with the roms themselves.

Has anyone had the same problem?

Does anyone know of any good freeware that will allow me to access/recover the game files without the need to reformat?
Failing that, any good freeware that will allow me to recover the files after re-formatting?!