Adding a new computer to Zune Pass without the Zune Device?

I just bought a new computer after my old one died unrecoverably. I had Zune Pass on that computer, and I’d like to add the new one, but I have long since lost the old Zune mp3 player I used. How do I add Zune Pass to this computer, or will I have to create a new account and buy a new Zune Pass? I still have nearly 3 months on this one. I’ve already downloaded the Zune software on this computer.