My friend recently gave me an old 20gb iPod. I don't know the exact generation, but it is a black and white screen, a white iPod, and has a click wheel vs the original wheel. It is something like 4th generation of the original iPods.
First things first of course. When I plug it into my computer initially, the computer doesn't recognize its existence, but I figure that because it is an old iPod that a battery that is too low on power may cause an issue. The battery is obviously empty, or at least very very close. The screen displays the image below on attempt to turn it on.

I thought, low battery, no big deal, it just needs a charge. The bigger issue is that even with a 20 minute charge on a computer and my iPod clock/dock it does finally turn on, but shows a less than satisfactory image. From what I've read, it is the failing hard drive image (below). The hard drive also emits an audible whirring noise when it tries to turn on, another sign that the hard drive is either gone, or very close to it.

The above is the exact iPod I have too. I can provide other info about my specific iPod if needed.
I've read up several ways on how to fix this, but many of them require a format that my computer won't recognize the device as to do so. My computer acted the way it did when I tried to make it read (unknown to me at the time) a dead MicroSD card. I'm also having lots of issues attempting to even open the iPod, as no easy was was made to do so since Apple would prefer sucking people dry for cash instead of giving them an easy and cheaper way to do it themselves.
Note: I've upgraded to Windows 7 since I last tried on Vista. Windows 7 doesn't even recognize the devices existence, while Vista nearly crashed until I unplugged the device while trying to read it before.
Basically, do any of you know of a simple way to fix this that doesn't require opening the iPod to replace the hard drive? If not, can I get a site or something where I can pick up a hard drive (some simple googling should reveal what model of hard drive to look for), preferably on the cheap (under $20 if possible)? If so, I'll also need an easy way to open it that preferably wouldn't require an extra purchase of a tool to do so.
Any and all help would be appreciated. I'll give updates as I figure out more about the issue. This thing beats my old 1gb 1st gen Nano if I can get it working though.
Thanks in advance to any help given.