how do i authorize?

Please, please, please help. I have been trying all sorts of fixes since Monday.    Apparently I installed the Adobe Digital Edition without authorizing my computer. I have an e-book I want to down load but it will not let me authorize for my desktop.  I can download the eBook on my I-pad through another program but the problem is I need it on the desktop. I uninstalled adobe Digital Editions and tried to re-installed ADE_4.0 Installer but i do not get an opportunity to authorize. What do I do?

i have pressed ctrl-shift and D to unauthorize the computer but when i sign back in and put in the adobe ID and password (which i have reset numberous times) push authorize ti gives me a message "incorrect login ID or password for the selected ebook vendor"