New battery not charging
I have a 10 gig, 1st generation iPod (yes, from 2002!) that won't charge. I bought and installed a new Newer Tech battery. When I plug it in, it powers up and the battery icon shows it charging. After a few minutes the screen goes blank. When it is disconnected from power it is dead. I have restored from iTunes and hard reset with no success. (BTW, when I hard reset while connected to power (press and hold menu and play) the screen goes blank, then momentarily flashes the dead battery icon, then the apple logo and powers up.)
Sounds like the case. Although the connection to the rest of the iPod may be incorrect, you could try opening it up and checking that
this is no an answerer , i had the same problem, and i can not see how to power on.