Drag the title bar of a window to the left or right side of the screen until an outline of the expanded window appears.
Release the mouse to expand the window.
Repeat steps 1 and 2 with another window to arrange the windows side by side.
To return a window to its original size click the Maximize button in the window’s title bar and the window expands to full size.
Windows Vista and Windows XP
In Windows Vista and Windows XP, it’s easy to display any two (or more) windows side by side on the desktop, all equally sized. Press and hold the Ctrl key and click two or more of the window buttons on the taskbar that you want to open. Release the Ctrl key, right-click, and then do one of the following:
Windows Vista users, click Show Windows Side by Side.
Windows XP, Tile Vertically command.