Q: Missing songs purchased on iTunes

Hi,

I recently purchased a new windows PC and downloaded my library from iTunes into it. However, some of my purchased songs didn't download, and I'm trying to figure out how to get them back. They are songs from albums that are no longer sold on iTunes (from Fleetwood Mac). I still have the songs on my iPad, but can't find a way to transfer them to the PC. The songs still show up in my history of purchases on iTunes, but not in the list of purchased songs available for download. Any help with this would be appreciated.