Windows Vista sidebar gadgets appeared as a separate application only in Windows Vista. It annoyed many people and often turned off.
Want it back?
It’s quite easy to do.
Start in Control Panel.
Double click on Windows Sidebar Properties and the answer to your question should be fairly clear.
Make sure that “Start Sidebar when Windows starts” is checked, and it’ll reappear when you next start Windows.
If you’d like to start it immediately, click on the Start menu, All Programs, Accessories, Windows Sidebar and it’ll start right up.
If the Windows Sidebar is running, you can see the list of running gadgets by clicking on “View list of running gadgets” in the Sidebar’s control panel app.
Here you can remove any gadgets you don’t like.
To add gadgets right click on the Windows Sidebar icon in the notification area.
Click on Add Gadgets… and you’ll get the interface for doing just that.