Older Ipod is stuck on "plug into power" picture. help?

My old 40gb Ipod continues to be stuck on the screen that shows a picture of the wall outlet and charger... I've conected it to power, the computor, and even restarted it using the menu-enter ons. After using the restart while it is plugged in it will temporarily get the charging battery screen then the apple will appear, and the plug into wall picture reappears. How do I fix my Ipod to normal useage abilities?