Lost the Endnote X7 Key purchased in 2013


I purchased Endnote X7 from UPMC Pittsburgh Book Store in 2013 and installed on my Mac Book Pro and Dell laptop. Since than I am using it without any problem, but recently MacBook becomes non functional and I would like to use it on my desktop & another new Dell laptop. I don’t have key but have programme file installed on my old Dell Laptop. How can I install it on my new system? I remember I may have given my email lokendra.sharma@chp.edu at that time, but since I returned to India way back in 2014, it my not work. Please let me know how can I use it.