Momentary flashes back to desktop

Hi all,

First time here.

I have an Alienware X17 r2. When playing a game (Battlefront, Combat Mission Normandy), the screen flashes very quickly back to the desktop 'Alien' image, then back to the game. This occurs seemingly randomly and the image flashes onto the screen only for a fraction of a second, before it goes back to the game.

The game plays with no problems (apart from this). The flash occurs maybe once every 10 minutes (basically randomly) or so, and what is happening in the game (i.e. whether on map, or command page etc) seems to have no significance.

Anybody got any ideas for a cure?

Thanks, Rich.