The image on the monitor is should be centered; however, new programs and new computers sometimes change this setting. To begin fixing it, locate the menu button on the outside portion of the monitor. This button has a small drawing of a list on it. Press this button.
A small list of different options will appear on the screen. Using the + and - buttons located near the menu button, navigate the list to find the "Auto Adjust" option. Once this option is highlighted, press the menu button again. This will make the monitor adjust the image to be centered on the screen.
If for some reason this does not work, press the menu button once again and/or (if the menu is already up) navigate to the option titled "Positioning". This will allow manual adjustment to the screen. Scroll to the "horizontal" or "vertical" option using the + and - buttons. Adjust the screen accordingly. After the screen is in place, do not touch any of the buttons and the menu bar will close itself.