@thecat847 your Zune needs a new battery. The Zune1126 is a second gen Zune 80, whereas the 120GB version is the 1376. Both should come apart the same way. Since iFixit does not yet have a specific guide, use something like [link|https://www.dailymotion.com/video/xjcm3y|this video] or the instructions [link|https://www.repairsuniverse.com/blogs/repair-guides/zune-120-gb-take-apart-repair-guide|from here] as your guide. Batteries are still widely available.
While you work on your Zune, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
Repair is War on Entropy!