How to deactivate existing license and reactivate the new license

I was using MATLAB2016b over last year. I was using academic license that expired on 31-12-2016. I am unable to activate it with the current activation key. I also tried to activate it using my mathworks account, that is the official email ID provided by the university. I have attached the error details that occurred to me. I looked to the corresponding solutions as well. In the solution it has been asked to launch the MATLAB first. But I am unable to launch it. Please let me know how to solve this problem?

Answer 1

[Walter Roberson]

The activation key you are attempting to use has already expired.