Adobe photoshop [Elements] old version

I have a old adode photoshop elements 15 code that I got when I got my new camera. My computer died shortly after getting the code but I never redeemed it on that computer. I have just been gifted a new computer and was looking to see if it still worked but came back to say the code was no longer valid. As I previously have never redeemed the code I was looking to see if there was a way of obtaining a new code to be able to download adobe photoshop or if I have to purchase a new copy?

[ Subject edited to include "Elements" by moderator for clarity]