Open programs no longer appear in task bar

Open programs no longer appear in the taskbar.  If I open a program it does not show up in the task bar.  If I minimize it it still does not show up.  However it still appears in the task manager.  I can switch between the programs as they are still open but do not appear in the taskbar.  I have Windows XP Home Edition with SP2.  I have gone through taskbar properties and did not find anything. Thanks for any help.