This tweak works only with Windows XP Professional. To make the notification area re-appear you need to use GPEDIT which is only available in Windows XP Professional.
1/ Click Start.
2/ From Start menu click Run.
3/ In the Run dialogue box type: gpedit.msc and click Ok.
4/ The group policy editor will now open.
5/ In the left hand pane look for User Configuration and then expand the Administrative templates section.
6/ Now click on the Start Menu and taskbar option.
7/ Now scroll down the list of items in the right hand pane.
8/ Look for the 'hide notification area' option, right click on it and then Click properties.
9/ In the properties window place a tick next to the 'not configured' option (if there is already a tick by this option and your notification tray is still not visible, then click the option marked disabled) Press OK to exit.
10/ Now look for the 'remove clock from system notification area' option and do exactly the same with that. Mark it as not configured.
11/ Again click OK to exit.
12/ Now exit group policy and restart your pc.
13/ KEEP EVERYTHING CROSSED and hopefully your notification area will return.