I'm a student with a deadline, so any quick response will be greatly appreciated.

I want to simulate waves on a beach. I was working on it at school, everything was working ok, but it needed tweaking. I open my save file at home, I no longer see my simulation. I am using the same Cache I was at school, I haven't play in the render settings or anything (using Karma).
I remember having to activate the Karma CPU in the Scene View to see my simulation, but I don't seem to have that option anymore. What is going on?

(I also have no faith that my teacher will answer, so you guys are my last hope, pretty much.)

You'll get the Karma CPU option when you display a LOP network, might be /stage or a custom one. Presumably that's what you were viewing at school.