My borrowed book will no longer open in ADE!

I have been using this for months with my ereader with no problems.  Now when I borrow a book from my library and download/open in EPUB from the library's website, it keeps asking me to download ADE again and again.  I allow it to do this but when I go to open ADE, there is not book there.  I am getting frustrated as this once worked and now it doesn't.  I removed ADE from my computer completely and reinstalled it.  I have authorized it, set up my adobe ID/password.  Still, when I go into overdrive and then into my library website, it won't allow me to borrow the book to ADE.  Any suggestions as to what is going on would be greatly appreciated.