Network, Volume, Battery icons vanished from system tray on Windows Vista

Scenario

My network icon has vanished from the system tray. Option is now unchecked and greyed out in Properties, Notification Area. It was there last night, just disappeared on booting up this morning.

Solution

Delete the 2 keys, by using Windows Registry Editor (regedit.exe through the Run feature), as per the screenshot.

[HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify]

Network, Volume, Battery icons vanished from system tray on Windows Vista

After the registry keys deletion, end and start the explorer.exe again, by using Task Manager.