In XP, that is called the Notification Area. As per your issue, it depends
on many things. Here are some checkpoints to consider:
This can happen by opening Accessibility Options, etc. If the icons on the
Quick Launch bar are showing as being larger, it will result in the taskbar
being twice its height and also include the date or similar under the clock.
If this is the case, right click the Desktop/Properties/Appearance/
Advanced. Under the Item drop box choose Caption Buttons and change the
number by one, ok your way out, then rest to 25.
And/or reset your default to the XP Theme. If need be, switch to Classic
first, then back to XP Style.
Other options to consider if the above doesn't help, nor moving the glider
over toward the Start Button to list only three icons in the Quick Launch
bar:
Restore the Taskbar to Default Functionality (Line 164)
http://www.kellys-korner-xp.com/xp_tweaks.htm
Hope all goes well and keep us posted.

)
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Happy Holidays,
Kelly (MS-MVP)
Troubleshooting Windows XP
http://www.kellys-korner-xp.com