After Effects problem causing my computer to freeze

I am learning the tutorials of the After Effects. I try to preview the composition but the RAM and the frames getting higher. And I mimzise the window to hear what it's talking, but when I re-open the window, it is freezing and saying the window is not responding. If you need me to capture the screenshot, this is why 👇

So, I waited in hours but the window is getting the f*ck out of me.