My Computer Won't Detect the Local Area Connectionby Dan Stone
Your computer needs to be correctly set up in order to detect a LAN; if there's any problem with the hardware or the connection itself, the computer will not register the network. Use Windows' network troubleshooting tool to identify the problem: right-click the Wi-Fi or Ethernet icon on the Taskbar in Desktop mode and select "Troubleshoot Problems." If your computer isn't showing a network icon, it may not have a network adapter installed.
If you're using a wired Ethernet connection, make sure that the cable is properly connected. Network cables can get knocked loose or may have a broken locking mechanism that prevents them from staying in place. Disconnect and reconnect both ends of the cable to the computer and network switch or hub. If the network switch or hub is connected to a parent network switch or hub, check that connection as well.
Adapter Turned Off
Some laptops have buttons and keyboard shortcuts for disabling network adapters in order to improve battery life. If your laptop supports network disabling, it won't be able to recognize local area connections if the adapter is turned off. Enable the adapter by pressing the appropriate button or keyboard shortcut. Additionally, check the power to any network hardware to make sure it's turned on.
Missing Network Adapter
Windows automatically installs generic drivers for network adapters during installation, but those drivers don't always work, or may not be installed at all if you've changed the computer's network adapter. The network adapter drivers may also be uninstalled or damaged through malware infections and file corruption, which disables the device. This means that if the device stops working for no apparent reason, you may need to remove some malware. If you're using an external network adapter, disconnect the device, reboot the computer, and then reconnect the device after the system has finished loading to initiate the automatic installation. If you have an internal device, uninstall it using the Device Manager (see Resources), and then reboot the system to activate the auto-installer.
Damaged Cables and Adapters
You may also experience problems connecting to the LAN because the network adapter or a cable is damaged. For example, Wi-Fi network adapters may not be able to get a signal if the antenna is damaged or disconnected, and a bad cable may not be able to complete the physical connection between devices, in which case you must replace or repair the damaged cable. You can test for bad network adapters by plugging in and using a different external network adapter -- if the second adapter works, there may be a problem with the first one.
- HP Support: Home Network Troubleshooting
- IBM: Troubleshooting Ethernet Network Connetivity Issues
- Dartmouth College: Windows Network Troubleshooting
- PCWorld: Windows Networking: Troubleshooting Tips
- Linksys: Network Magic Frequently Asked Questions
- PCMag.com: 12 Tips for Troubleshooting Your Internet Connection
- Microsoft Windows: Why Can't I Find a Wireless Network?
- Microsoft Windows: Troubleshoot Network Connection Problems
- Microsoft TechNet: Uninstall or Reinstall a Device