Make sure your web browser window is "maximized" and takes up your entire computer screen. There are many ways to do this, but often there will be "minimize", "maximize", and "close" icons on the top right of your browser window. Click on the "maximize" icon.
Pearson online products are designed to work effectively with screen resolution set at 1027 by 768 or higher. Change your computer's display settings to resolve the issue. To do this, click on Start --> Control Panel --> search for Display.