Have a look in you network connections first.
Right click on the Local Area icon and check the properties to see if the LAN is enabled or disabled. If that does not work you could
try running the networking wizzard again.
To check the settings:
Start--->Control Panel---> Network and Internet Connection--->Network Connections. in that section you will be able to see your Lan/internet connections, and you can also set-up your Home or small office network.