Why won't my Ipod turn off if unplugged?

Hi there,

I was charging my sister's IPOD from last night and 1. it's not fully charged which is strange as it was plugged in all night and 2. when I unplug it, it won't turn on. It only turns on when the IPOD is plugged into the computer, however it just goes to the Connected (eject before disconnecting) screen. I already did the switching the top switch from black to orange for 3 seconds and I held down the menu and middle button down but still nothing. HELP!