I'm sorry to learn that your device is not taking screenshots, LJ2316. I understand that you are following the steps listed at this link (http://spr.ly/6602Ebqmm).
We are committed to assisting you as much as possible. Let's get some additional information.
When was the last time that you were able to take a screenshot with your phone?
Has the phone ever been dropped?
Is there any visible physical or water damage?