microsd 2gb card....deleting files from same HOW???

Hi Guys pse help....have recently acquired m3simply for ds lite and loaded with micro sd 2gb card.
Loaded all operating file and some games!! But just NOT working
In an attempt to clear and restart I placed micro card back into card reader and attempted to delete All card entries.....

But system will not delete states "Cannot delete files.Cannot read from source file or disk"


How can this be when PC recognises card reader in J drive,shows the files installed by myself on virgin card??????:confused:confused

Is there any way I can empty micro card ??????