Quickly increase and decrease the size of Desktop icons
In Windows Vista and later versions of Windows, while on the Desktop, hold down the Ctrl key and scroll up and down using the wheel on your mouse. When scrolling up, all the icons on the desktop will increase in size. When scrolling down, all the icons will decrease in size.
While you hold down Ctrl, icon text will increase or decrease in size when scrolling up or down with the mouse wheel.
If you don't have a scroll wheel on your computer mouse, or you are using a laptop and don't use a mouse, you can do the following.