Hi kertisaw!
Maybe you have a borrowed book from a public library. Try the following:
1. On the upper right corner click on the "List View" button (the one with horizontal lines)
2. Check the name of the expired book and you can delete by giving a right click.
If the ebooks are all from the Reader Store, then Adobe authorization got corrupted. Try the following:
1. Sign in to your eBook Store account
2. Click "My Account" at the top of the page
3. Click on Manage / Rename Devices
4. Click "Deauthorize" for the computer you are using
5. You will be automatically logged out
6. Sign back in
Check on your library if the problem persist.
GoodLuck!
eBookBoy
http://digialreader.freeforums.org/