Adobe digital editions

Hi, I just got a new laptop, and it will not authorize my new computer so I can read a textbook for school. It still works on my old computer, but will not allow me to deauthorize my old computer, and then authorize my new computer. It has been nothing short of a nightmare, as I cannot get any of the 'help' tips to work. Can someone please help me. It actually just disappeared completely from my library, and will not allow me to re download it into the digital editions.