NIS not respecting full screen app

I'm currently running NIS 2014. My understanding is that it is not supposed to run when you're running a full screen app.

 

I've noticed that while I'm playing NWN2, my performance tanks and the game gets very laggy/locks up every few minutes. When I checked the NIS performance tab, it showed that NIS.exe was running every few minutes, maxing my cpu, while playing the game.

 

I'm playing a single player, offline game. No downloading, etc. going on in the background. How do I get NIS to stop running while I'm trying to play a game?

 

FYI, I'm  running WinXP on an old P4 system.