Do you have a wordpress.com blog? I f so please post the url.
If you have a wordpress.com blog then you have a Top Posts widget. -> Presentation – > Widgets – simply locate it in the “available Widgets” box and drag and drop it into the “Sidebar” box . By clicking on the blue and white icon you can open the widget and set it to show up to 12 of your top posts. Then click the X on the corner of the widget to close it. Lastly, click “Save Changes”. Now the Top Posts will display in your sidebar.