You must make sure your authorization is still the same as before.
Sometimes ADE gets its registration/activation confused and in a semi-authorized state.
Uninstalling and reinstalling does not help, and indeed installation can even trigger this state. (your upgrade could have done so as well)
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.
Another is "E_AUTH_NOT_READY"
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 input. I'm afraid I'm out of luck as I can't remember what id I originally setup with Vista. I think the DRM books are tied to that id and won't let me access them.
If it really mattters and you are patient, and if Adobe support are helpful (some hope) you may be able to recover it by
OK. To find the internal AdobeID.
open a sample DRM .epub file as a .zip file.
With some zip programs, you can just open the .epub as an archive (ev, with 7zip),
with others you will have to rename the .epub file to a .zip file first, then open it.
find the file 'rights.xml' within the zip. Probably 'META-INF\rights.xml'
open the rights.xml file
inside you will find a section '<user>' that looks something like
That string is the internal version for your AdobeID.
That stays fixed for the AdobeID, even if you change the associated email (or password),
that internal ID is what is really associated with the book.
(n.b. there is no point in trying to change the urn to a current one you might find and recreating the .epub file; the DRM is cleverer than that).
You can now contact Adobe at Adobe Live Chat: http://www.adobe.com/support/chat/ivrchat.html
It may be that if you can give them that internal ID they will be able to get you access to your account again.
If they say they can't, it might be worth trying two or three times at intervals;
it seems from what others have said that some of the representatives are very clued up, but others are not.
(I've never used the Live Chat).
If you do go through all that, let us know how you got on.