Can't take in-game action screenshots

Hi there,

I'm having a fair bit of trouble taking screenshots with my new Alienware 17(OS Windows 10.). The only way I can take instant screenshots (i.e. without the Snipping Tool) is by using the windows key, the FN key and the Print Screen key at the same time. It's a bit of a scramble, but I can manage it.

However, when I try to take in-game shots using these 3 keys, it often can only take one screenshot of the actual game - then the game window closes and it goes to the Desktop (which is due, I think, to the Windows key being pressed.) After that, whenever I press the three keys, it just takes a screenshot of whatever is behind the game. Recently it doesn't even take the first screenshot, it just keeps taking shots of the desktop/open Word documents I have open. 

Anyone can help me out here? It's a bit frustrating, and I miss the old Prt Scrn option, it was just so much easier.