I use dial-up connection and i could see network status icon in notification area, but now whenever i connect to internet, there is no network icons.
i also went to this path:Right click on start>properties>Notificaton area.........but the network checkbox was thourouly disabled .What is the problem?thanks for your answers.

Check in Device Manager (Start...type in "devmgmt.msc" (without the quotes) and press Enter) to see if the network card is having any problems.