I had a similar problem with sniper ghost warrior 2 in that the game would start tab out and become unresponsive. For me it was caused by msi afterburner so close that if you have it. you could also try closing any other monitoring software if you have something different.
So, apparently I am victim of a save game bug. I was fortunate enough to find someone who was sharing a completed game save file download on another forum. This seems to have fixed my problem. Thanks though, I hope ghost warrior 2 works out for you.