My iPod (video) won't charge or connect/sync, but turns on. Battery?

So here's the situation.

I have an iPod video 5th generation (late 2006 model). It's worked for years in the past, but then the cord was replaced. It was replaced with a cheap Hong Kong charger.... but the iPod seemed to not be charging after that, so it was left alone for years. Like I said, it was sitting around for years. I got it out recently, and tried to charge it via the Hong Kong and an official apple cord, and here's what happens with either cord:

When plugged in, it displays the "Very Low Battery, Please Wait" screen. After a minute or two, it powers on, but only shows a small red line in the battery symbol (upper right on the screen). No appearance of charging at all. On the computer, it plays the sound when devices are plugged in, but only shows a "USB device not recognized" message. Nothing shows up in iTunes or "My Computer". Also, the "Unknown device" on my computer gives a "code 43" error code.

I'm thinking it's the battery, but I want to be sure before buying a new one. Please give any helpful info you can. Thanks!

Other info:

I use Windows 7, and the iPod is configured to Windows.

I've tried resetting it, and putting it into disk mode, but nothing changes.

I've taken it apart, but nothing seemed to be out of the ordinary.

I've tried connecting it to a different computer, but the same sequence occurs.

oldturkey03: I have tried connecting it when it's in disk mode, but it didn't change anything.

Hey guys, thanks for working with me on this. I've decided that I don't really need to fix it, and I've pretty much tried everything already. Thanks so much for your answers, though!