If you have a lot of icons on your desktop and you want to make more space, or if you just like the less-cluttered look of small icons, Windows allows you to reset the default icon size. In Windows Vista and 7, you can quickly change your settings right from your desktop. In Windows XP, you can decrease the size of your icons in the "Appearance" menu.
Windows Vista and 7
Right-click on any blank area of your desktop.
Place your mouse cursor over "View."
Click "Classic Icons" to set your icons to the smallest available size.
Right-click on your desktop, and click "Properties."
Select "Appearance" and "Advanced."
Click the arrow to display the "Item" list, and select "Icon."
Choose a smaller number in the "Size" box.
Try using the scroll wheel of your mouse to resize icons. Just press and hold the "CTRL" key, and move the wheel to adjust the size of your icons.