You can deregister the Sony by hitting ctrl-shift-E to ADE (cmd-shift-E if using a Mac) with the Sony plugged in.
Then restart ADE, and reregister the device with the new AdobeID (that is, the AdobeID currently registered on ADE itself).
If you reauthenticate with a new Adobe ID, you will no longer be able to read any of the DRM books already on the device.
I can't see any way to find out which AdobeID you are currently registered with (I can see the uuid but not the user name).
Hi, thanks. I know that I'll lose all my books, but that's no big deal, because I only had books from the library... But I'll try this!
There are bugs on ADE 2.0 that mean the Sony PRS-350 will not work with library books on ADE2.0.
May well be the same with PRS-650.
If so, replace ADE2.0 with the more reliable v1.7.2.
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172