Normally, everything that is added to the sidebar is Widget...
In your WP admin, (I'm sorry I don't have the English word), if you place your cursor on "apparence", just above Extensions, you will see Widgets.
Click on Widgets.
On this page, you should see on your right Primary. If it is not developped, click on the little arrow at the right and you will see all the widgets installed in your sidebar. Just delete the ones you don't want...
Hope it helps!