I created a thread a week or two ago about an issue I was having with games auto-minimizing themselves to the desktop for no reason but came across this the other day which I thought was worth posting here:

http://www.guru3d.com/news-story/windows-10-kb3213986-update-can-cripple-multi-monitor-gaming.html

I have my PC connected to just one TV at the moment. Occasionally my games will minimize out, but it's not frequent enough for me to have an idea as to why.

I have deffered updates so hopefully i haven't downloaded this yet, haven't had major issues with my 2 monitors so far. Windows forced updates need to go though, i dont know who thought that was a good idea.

Sometimes games get freaky when it isn't expecting a dual monitor setup. I had to mess around a bit to get things working, specifically forcing DOOM to choose the correct monitor at the correct resolution with full screen. For some reason it wanted to put me in windowed mode with some crazy resolution on the wrong monitor. One trick I found with those types of games is to start the game with one monitor on, configure everything, exit out of the game, turn the second monitor on and then start the game again.

One thing i do is hit "windows key + P" and select the monitor i want (second or primary) only and that usually works, although some scaling issues can happen in some games. Also you won't be able to use the second monitor, which i hardly do when gaming anyway.

I believe that if system is infected with virus then also it can create such error.