why is my ipod photo only shows an apple logo when i try to open it then fades?

i just do not know what to do with my 40gb ipod photo color. whenever i tried to open my ipod...an apple logo appears for about 10 seconds then little by little fades until it's gone. sometimes after the apple logo a battery icon appears... sometimes a folder icon...and sometimes a sad face icon. im confused about what is really wrong with my ipod. is there hope that it will rise again? could someone please help me with my ipod. thank you.