For most desktop shortcuts you can change the appearance by right-clicking the icon, selecting Properties and clicking the Change Icon button on the Shortcut tab of the dialog. If you tried to set the My Computer icon with Windows 7 in this manner, however, you quickly learned that it does not work. Changing the icon is not difficult, though, once you know where to look.'

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Right-click any blank area of your desktop (basically anywhere besides on an icon). Select Personalize. The Appearance and Personalization window will open. Click the Change Desktop Icons link in the left pane of the window. The Desktop Icon Settings dialog box will open.
Click the Computer icon in the main window of the dialog box and click Change Icon. The Change Icon dialog will open next. Find the icon you want to use instead of the default My Computer icon and click OK. Click Apply to save the changes. You can also change the icons for other desktop items here, such as your Recycle Bin or your Control Panel. If you change your mind, simply click the Restore Default button. When you are finished changing icons, click OK to close the dialog and then close the Appearance and Personalization window. The icon will be changed both on your desktop and in your Start menu.