There are always a lot of reason why it may not work. At first check ALL return code of used function, because you may miss some access rights.
Another plain reason and my best guess is always that your code is drawing at some invisible coordinates. So try to make the drawing windows full screen when at the main monitor to see something.
Consider creating an extra output child window. Dig in the drawing code to control the output coordinates.
bonus tip: write some output in some function to see that
pictureBoxDisplay.Paint += new PaintEventHandler(drawLatestImage);
is really called and you not only are guessing with a lamp.