Where are the quick launch buttons on my toolbar defined?

A. The quick launch bar, which provides easy access to your favorite applications, appears beside your Start button. Traditionally, you can add shortcuts to the quick launch bar by simply dragging a file onto it and selecting "Create shortcut here" from the context menu. To remove items, simply right-click the shortcut, and select "Delete from the context menu."

You can also manually control these shortcuts by adding/removing entries in the C:\Documents and Settings\\[user name\]\Application Data\Microsoft\Internet Explorer\Quick Launch folder.