Open programs not shown in Taskbar

Normally the Windows desktop displays the current running programs/windows in the taskbar, right?

After I restarted windows the other day, the open programs/windows won't show on the taskbar. This has happened before and I don't know why.

Anyone know why this happens and how to fix it?

All-in-one repair tool:

http://www.kellys-korner-xp.com/taskbarplus!.htm

Looks like a scam to me ~_~

http://geoshell.org/