Hi Maryse,
From what I understand, you have a Student Serial Number for Maya 2014 which you have downloaded from the Education Community Site. Meaning, you already have the 900-xxxxxxxx Serial Number for Maya 2014, correct? If that's the case, all you need to do is to download the 2014 installation files, which you can get from the Education Community site or from our Virtual Agent.
Once you have downloaded and installed it to the new machine, it will take you automatically to the Activation Page. Once you reach that page, you just have to input your Serial Number and Product Key. Afterwhich, it should be good to go.
Reply back and let me know if you need more clarification.