I cannot get ADE to authorize my Kobo. Please help!

I have been using my ereader for library books for over a year, now I cannot get ADE to authorize my ereader. I have tried a factory reset. I have tried deleting and reloading ADE versions 3.0 and 4.5. When I click on authorize device, nothing happens. My computer is already authorized and I can read books on my computer, but I just cannot get ADE to authorize my ereader.