how do i fix my packard bell audiodream 1gb mp3 player?

i tried putting songs onto it...but it doesnt play them, i can see them when i connect it to my pc but they are non-existent on my mp3 player.
When i look at the memory usage on it, it says 0mb used 0 mb free....ehm?????
it's not like i've added blank file on because i tried it on another pc and i can play them through that....it says i have no files on it when i try to play them...also when i tried deleting them...it took ages but eventually i deleted them but later when i plugged it in again..they were back!!!!! mp3 players are extremely frustrating.