Broken balance rod?
Thanks for reaching out to us! There are a number of factors that could be contributing to why the balance will not install in the window properly. Unfortunately, the photos do not provide enough information to determine exact why.
I've included a few different video tutorials below that show how to remove/install the balances and how to replace the top sash guides. Take a look over them to see if that might give you a better idea.
If you are looking to replace the balance? I'll need to know the length of the balance (excluding the attachments) and the stamp from the channel.
Please don't hesitate to reach out with any other questions you might have.