Has your iPod gone for a swim? look at the water damage indicator.
This indicator will remain red, even if you have dried the ipod thoroughly, till it is replaced by a new indicator.
if it is red, then yes time to buy a new iPod
if not, then your battery is dead, connecting the iPod to the PC, will display a charging screen after 30 miutes.
But if after 30 minutes and there is still no life on the iPod screen, try another USB 2.0 port, at the back of the PC, dont use the port at the front of the PC.
If that doesn't work, try using another USB cable, or buy a wall USB charger and try to charge the iPod.
Have a nice day!