System Tray program icons not appearing for startup items

Archived from groups: microsoft.public.windowsxp.basics,microsoft.public.windowsxp.general (More info?)

This issue has actually been going on since before the days of SP1 and
happens to all my computers.

I have a few programs that load on Windows startup - some places an
entry in the Registry, others a shortcut in Startup folder in the Start
Menu. When these programs load, they place themselves as a System Tray
icon. After a few sessions, these programs icons stop appearing in
System Tray on startup. The corresponding programs continue to load on
startup and I can see them running when I look in Windows Task Manager's
Processes tab, just no tray icons. The only way I can get the icons
back in System Tray is to stop the process in Task Manager and reload
each program manually, but when my computer reboots, the situation
repeats itself. Sometimes even the unplugged Local Area Connection icon
doesn't show up in system tray when my LAN cable is unplugged on startup
.. Sometimes when Windows Explorer crashes and reloads itself
immediately after, some of these tray icons will reappear, but not
always. This doesn't happen to programs I manually load after Windows
finishes booting up.

What is causing the system tray icons to not appear when my programs
load on startup and is there a fix?

Thank you so much.