You seem to have a mix of problems, this may help or ...???
Sometimes ADE gets its registration/activation confused and in a semi-authorized state.
Uninstalling and reinstalling does not help.
Unfortunately, it often then gives misleading error messages about what is wrong.
A common incorrect message informs you that the ID is already in use on another computer and cannot be reused.
This can often be resolved by completely removing any authorization using ctrl-shift-D to the Library screen on ADE (cmd-shift-D if on Mac).
Restart ADE, and then reauthorize with your (old) Adobe ID.
In extreme cases on the mac, the following extra step has helped some people. Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash. If you are using 10.7, see Access hidden user library files | Mac OS 10.7 Lion. http://forums.adobe.com/thread/1265248?tstart=0
Thanks for your speedy response but I am still trying to resolve my e-reader problem. I completely removed auth. as advised and that did not work. I then uninstalled 2.0 completely and did a complete re-install. I then tried to open trial e-book and now I am getting message on computer that it cannot open because adobe reader cannot open the URLLINK.acsm because it is either not supported or has been damaged and wasn't correctly decoded. I downloaded 3 different times but it will not open. I also now cannot open any of the books on my computer which was not a problem before. I checked if I needed to update Adobe Reader but no updates were needed and it is working fine. I am running Adobe Reader Vers.9.5.5 on computer and e-reader is vers. 9.1.288890. I also re-checked my network and allowed Digital Editions through the firewall. Is there any easy solution you can recommend? I'm running Windows 7 and using IE 10. Also
reading all the other Q&A but still struggling.
Thanks for your assistance.