got a new laptop wont download my library book say liscened to an other user

I know I did not make it too clear I was frustrated at the time. I finally fixed it, I was trying to check out the same book I had checked out on my other laptop before it died. I downloaded a random book and it worked, I just cant get the original  one I had until it is returned to the library. Thank you for responding though, I really appreciate it, this was the first time I used a forum and wasn't sure how it worked, but there is a lot of helpful information here.