Having been there, done that, finding no help on the web, I broke down
& called Microsoft support.
If your hard drive has been replaced & your eBooks won't open, and you
get an activate error when you try to reactivate, what you do is open
IE, go to the internet settings on the tool bar & delete your cookies,
delete your temporary internet files & clear your history. Now you'll
be able to reactivate w/out any problem & you're back in business - at
least that worked for me.
Irene Newhouse