Exclamation point and folder and nothing else

Hi... I have an older 20 g iPod. I dropped it (only 3 feet but hard surface) last week and after that it malfunctioned and then stopped functioning. I have tried the reset several times without success. My Mac does not recognize it either in the information about this Mac or the disk utility or the iPod updater. I would love to be able to revive it but had assuimed it dead. I can get an apple on the screen when I do a reset and the battery icon shows that it is charging ... and then the exclamation point with the folder comes up.

Any thoughts would be more than appreciated. Kay