I have a Dell and trying to play my downloaded songs from itunes. I get a message that my computer is not authorized. ???

I just purchased a Dell XPS 12/Windows 8

I downloaded itunes to my laptop and can get into my itunes account and see my playlists - but when I try to play them, I get a pop-up that tells me my computer is authorized. There is not option to correct this and when I called Apple support - they told me they could not help me.

Does anyone know how to correct this?