ttds advance memory card cant read

I jus bought my ttds advance ytd n was fine until the next morning when i on my ds,the picture of the memry card sudden says error....wad to do..
Even tried moving all files to comp still dint work.. :-[Help realli needed...thx

Backup your files, format your microSD, and reinstall your latest firmware.Look here for a MicroSD formatting program.
http://www.sdcard.org/consumers/formatter/

if you look in the sd card and there is a strange folder, there has been a serious problem and you cant back it up its happened to me ONCE. If this is the case; I hope you still have all your stuff on the PC... And just format the card to FAT32