I'm not that familiar with the XPS one since it only came out in the UK about a week ago to my knowledge but heres a few ideas:
a.) go to your my computer (or wherever you normally access your CD drive), right click on the drive icon and select eject.
b.) if that doesnt work then the CD may be physically jammed into the drive. You may need to disassemble the exterior to find the hardware eject button.
I have a dell xps 15z with a stuck turbo tax disk. It didn't begin install upon insertion as I would have expected. It isn't showing up on 'my computer'. there is no eject button or pin hole. i've restarted my computer 3x and haven't seen anyway to eject the disk. please help! Ready to throw this computer across the room!!