Spontaneous black box?

I keep using my laptop. Suddenly a black box in the corner with codes, I filmed a favorite scene in my series and you saw a part of it. What is it? (only part of the picture was shown)

This is the Windows Console. Probably some program is running in the background.

So actually it shouldn't open up. But that's the Windows command line you can run commands there, here is an example:

color 4 = change the color of the text

color gives you all possible colors

ls = Shows what is in the directory where you are at the moment.

Just google for Windows CMD or Windows command line.