iPod another sad ipod face 4th gen 20gb question

Okay I know that the sad Ipod face is common but here is my story. I received my ipod from my niece who didn't take very good care of it. It had gotten the sad ipod face regularly so she got a new one. Some how I took it apart and got it to function properly for about 10 months. One day after listening to it the ipod it froze up and all my songs were gone. It kept booting into disc mode. When I got home I tried to sync it up to the computer, it would recognize it for about 30sec then go to the sad ipod face. I figured that after it being dropped many times I would replace the hard drive. That didn't fix it. All it would do is continue to boot to sad ipod face then restart. I thought okay maybe the battery needs charged but I can't tell if it is charging since it is in a sad ipod face boot loop. I decided to replace the logic board since parts are fairly cheap and I used to fix expensive biotech equipment so it would be easy. I just put in my logic board yesterday and it still just boot loops. Anyone have any clues? The next thing I can do is buy a new battery but I doubt that will work. I am trying to get the PC to recognize it so I can reformat the drive then load the proper software onto it. Please help....hopefully this post makes sense.

pretty sure the buttons are fine. I figured I'd replace the battery and try that. As for the logic board it's here but the connector for the hard drive broke off so don't think you want it.