Even though the sidebar is missing from Windows 7, you can still use gadgets much as you did in Windows Vista. It’s just that now, gadgets reside directly on the desktop instead of in a special area.
Microsoft gave the sidebar a major overhaul in Windows 7 by removing the familiar bar at the edge of the screen and replacing it with the Windows Gadget Platform. Now, gadgets float around the desktop rather than being confined to a special area of the screen.
To place a gadget on the desktop, begin by clicking on Start and typing the word Gadgets into the Search Programs and Files box. Press Enter and the gadgets window will open showing you all the gadgets you have installed on your computer.

click to enlarge
To add a gadget to the desktop, simply drag any gadget icon to your desktop. Some gadgets have customizable options and can be made to occupy more or less space on the desktop.

click to enlarge
Dragging gadgets near one another will cause them to snap together so you can create an uncluttered appearance. Individual gadgets will also snap to the sides of the desktop and into the corners in case you want to stack them and create a neat array of tools.