If you have a picture or shape on a slide in PowerPoint, you may sometimes want to only move it in the same vertical or horizontal plane. How do you drag the picture to move it on the slide but keep it in the vertical or horizontal plane? Just press Shift when you are dragging. You can then only move it exactly vertically or horizontally. Make sure you keep the Shift key down until you let go the mouse button.
You can also use this technique in Word and Excel if you have added a picture or shape to the file.