Adobe digital editions 4.5

Hello, 

I purchased a book last may, when i downloaded it , i was asked to also download adobe digital to access it. I marked the book since I have been working on it a lot, so i want this version back. My computer crashed yesterday. I purchased a new one , tryed to access the book and impossible. Adobe requests a password and a usernale i do not have. the online assistant, says he cannot help since he is exclusive to subscriptions. how can i get my book with my marks back? thank you for your help