How do you get a screen shot

Any search I do on screenshot overwhelms me and I haven't figured it out yet so I need some help.
On anything else I press "Alt" amd "Print screen" and then paste the picture into Paint and I have a picture of what was on the screen.
But when I do that in Railworks all I get is the opening screen of the game.
Anyone have an idea of what I'm not doing right?
Thanks
Dave
On anything else I press "Alt" amd "Print screen" and then paste the picture into Paint and I have a picture of what was on the screen.
But when I do that in Railworks all I get is the opening screen of the game.
Anyone have an idea of what I'm not doing right?
Thanks
Dave