Users of Windows Vista operating system may run into a scenario where the volume and the network icons could go missing. To get around this problem one needs to check the Taskbar properties. Under this option, one needs to make the relevant changes to the notification area and restart the computer. If the volume and network icons are still missing then the user needs to make changes to the registry. After deleting the relevant keys from the registry, the user will need to restart the system based on Windows Vista to make the changes effective.
Sometimes it may happen that the volume and network icons normally located in the notification area have gone missing.
To handle this issue:
Right click on a blank spot on the taskbar/properties.
Go to the Notification Area tab check the boxes for the options you want to have in the notification area.
Sometimes it is impossible to tick both boxes (they are grayed out); in this case, restart your PC and repeat the process.