How can I restore the default screen size?

stanley53 wrote:

have lost the display set up with toolbar and all other controls.

Well you certainly do not paint the most clear picture— but here is a guess:

>Stystem Preferences>General> Show and hide tool bar:

>System Preferences>Displays

Resolution Display default

stanley53 wrote:

I do not understand

If you do not understand 'default for display' Resolution, then maybe you should restate the question providing more detail about the the problem you are having and what you are experiencing in what environment (system wide?)

Go to the location specified and set the resolution to its default size.