Can't de-authorise Digital Editions on PC that crashed and now it doesn't work on new PC

My PC on which I had Digital Editions crashed and when I downloaded it (from Kalahari.com) onto my new PC and tried to open my e-books I got a message E LIC ALREADY FULFILLED BY ANOTHER USER. I was told by Kalahari.com to de-authorise Digital Editions on my old PC before downloading it onto the new one but I can't because the PC is kaput. I can't do anything on it; it's not working! How do I get Digital Editions to work on my new PC then?