Hi Ganbold, Animation Paper should run on most newer systems. I don’t think it is your hardware that is to blame for the strange thing that happens on your son’s Win10. Also reusing the key is not the problem.
What I am noticing is that Animation Paper apparently has approved your key, but never shows the main Animation Paper window for some weird reason. Do you have an extra monitor connected? Could it be that Animation Paper opens up on another desktop or on a disabled monitor or something. Somewhere our of view?
Is it running if you check in Task Manager?