Windows-based operating system have a graphical user interface, (GUI). These systems use icons, which appear in windows, to represent documents, applications and directories. Hard disk management can be achieved by managing little graphics or icons.
Windows are rectangles on the screen that show the contents of a disk, folder or document. Some windows, called dialogue boxes , show messages or offer choices.
It is possible to have more than one window open at one time. Only one window can be active at one time. The others are inactive. BTW, you are reading this inside a window.
