Sony PRS-650 not recognised in ADE

I have a Sony PRS-650.  Got a new PC, downloaded ADE, registered to Adobe ID and bought some ebooks.  ADE does not recognise my ereader so am unable to transfer ebooks to it.  Cannot see how to authorise ereader (Ctrl-shift-E as recommended by Adobe does not do anything).  Copying files using Windows Explorer does not work either as files are blocked by DRM.  How do I get ADE to 'see' my ereader??