4th gen iPod Battery issues

I have a black and white (screen) 4th gen 20gb iPod. It works fine when it's in the Bose Sounddock series II I recently bought, but when I take it off it completely turns off. I haven't used it in about a year since I bought a touch, so I thought maybe the battery was shot. It isn't too big of a deal considering I won't be carrying it around, but when I try to update it on my macbook pro it gives me a low battery signal and will never boot up.

What can I do to get it to load so iTunes will recognize it?

I left it on the sounddock overnight and this morning it still says that it is charging, but like I said, as soon as I pull it off it shuts down.

Is my computer not giving it enough power to run if the battery is indeed shot? What can I do?

Thanks for any advice!

The battery needs to be replaced. You can do the work yourself by going to this site: iFixit: The free repair manual Buy the new battery and follow their instructions for changing it.