Is there anyway to use my MI BOX that is connected to the tv as a "second screen" to my pc that just shows my pc screen if you understand (english not main language). Or do i need a long cable that goes from the TV screen to my PC or should i be able to use the MI box in some way or another. I am going to try Team viewer right now to see if that works, and i will go back to this post after im done to see if you have given any other ideas.
I am assuming that you are asking how to use the mi box as a secondary display or to mirror your current display?
The easiest way that I have found. Is to install Google Chrome on a computer and then install Chrome remote desktop on the Android device from the Play store. You might have to sideload it If running Android TV and not standard Android. But the app allows you to log in and out of your computer screen easily. I'm sure there's better ways. But that's the easiest I've found.
Use Moonlight. It's so good. I even use it to stream games from my pc. No lag and perfect picture quality. I highly recommend it!!
Cast your PC screen to TV using Chrome or Microsoft Edge