My operating system is Windows 7 Pro. I've been using Adobe Digital Editions for years a week ago I had a problem downloading e-books from the library and message popped up reading something like authentication needed…. So to try and problem solve I reinstalled ADE and try to download one of your trial books on your site and also from the library and got the following message "Error check activation". I contacted Adobe and they haven't formed me I have activation left. Please let me know how to move forward.