Most applications have three small icons
in the upper right corner of the screen that are used to minimize the
screen, maximize the screen, or exit the application.
By clicking on the Minimize button (the left button), the
application is placed on the taskbar. It is still open and can be
accessed simply by clicking on it in the taskbar.
The middle button, or the Maximize/Restore button, changes
depending on whether the window being viewed is opened partially or
fully. Click on this button to make the application screen smaller or
larger.

The far right button, marked with an "X", closes the
application.
Hint: the fastest way to minimize all windows quickly is to
click the Show Desktop icon next to the Start button.
Clicking the button again restores all windows.