why can't I charge my ipod gen 2 on my new Windows 8.1 computer?

Hello, jmjapple.

Thank you for visiting Apple Support Communities.

Here is some information you may find helpful when experiencing issues charging an iPod shuffle. Make sure to test with another charging cable and avoid using adapters.

For iPod shuffle (2nd generation)

To charge the battery using your computer:

1. Connect the iPod shuffle dock's USB connector into a high-power USB port on your computer.
   Note: To charge a iPod shuffle battery, connect the device to a high-power USB port. Please be aware that USB keyboards and non-powered USB hubs generally do not have high-power USB ports. If you connect to a low or non-powered port, iPod shuffle will not charge.
2. The computer must be turned on and set to not go to sleep.
3. Insert the iPod shuffle into the dock.
4. Verify the iPod shuffle is seated securely in the dock.

Once the iPod shuffle is plugged in, it will take about 2 hours to charge the battery to 80% capacity and about 4 hours to charge it to 100%. Find out how to check the battery charge here. For information on status lights while connected, click here.Note: The computer must be turned on and set to not go to sleep or hibernate.To charge the battery using an iPod USB Power Adapter:

1. Connect the AC plug adapter to the power adapter (they might already be connected).
2. Plug the USB connector of the iPod shuffle USB Cable or Dock into the power adapter.
3. Plug the power adapter into a working electrical outlet.
4. Connect the iPod shuffle to the dock.
5. Verify the iPod shuffle is connected securely.

iPod shuffle: How to charge the battery

http://support.apple.com/kb/HT1477

Cheers,

Jason H.