Cubase 4 download

I have lost my PC in which I’m running Cubase SE, so I am left with Mac G5 and I have no other choice for now. I can’t afford anything else. I downloaded Cubase4 from steinberg and have an elicenser but no activation code. Does anyone know how I can obtain one, I will pay if need be. Really don’t have any other options at the moment. Thanks please help, dying to record!!