HI, normally with the use of the windows key + arrow left/right, you can move a window from 1 screen to another.
To make sure that it's maximized, you could ALT+TAB.
Another way can be to make sure the windows has focus and with the ALT+SPACE, you open the system menu. With the key X you maximize the window and then again with ALT+SPACE & key M, you activate the move option. Just pressing the left/right arrow until the window appears.
Another, may more simple way, is to disable the second screen in your screen settings....