library disappeared

Hi,

I'm hoping someone can help me as I don't know what to do!

My version of ADE kept crashing and so I uninstalled and reinstalled it. I have authorised my computer but my library has disappeared. I tried opening my books again (ie adding them to the library) but I get an error message saying that the books already exist in the library.
When I plug in my Kobo e-reader ADE either crashes when I try to open it, or just shows 0 books in there too.

Any tips gratefully received!

Thank you

Hannah