Turning whatever's on the screen into an image

Here's what I'd like to do.

Let's say you're playing a game and then you press pause.

Here's the pause loop:

repeat
   cls
   drawimage (What the game looked like before they hit PAUSE),0,0
   drawtext,"PAUSED",in the center ;)
   flip
until someone unpauses the game ;)

Any ideas? :)