When you go to your control panel, browse into Network Connections (sometimes under Network and Internet Connections, click on Network Connections at the bottom right side of the screen) and find your network card is "disabled", you should right-click it and choose to enable it in order to use it.

If you enable it but the status does not change, you can safely follow these steps if your PC came with Windows XP already installed on it with the network card already installed.

• Open Device Manager (Start>RUN>devmgmt.msc>OK).   
• Expand your list of network adapters.   
• Find your wired Ethernet (not 1394 or wireless adapter).    If it is disabled (red circle with a line drawn through it), you can double-click it and choose to enable it and you should be finished.   
• If your adapter has an exclamation mark over it which tells you there is a driver issue. Right-click your Ethernet card and choose, "Uninstall". Click yes or OK to remove the device.   
• Once the adapter has disappeared from your list, click "Actions>Scan for Hardware changes" at the top of the device manager menu.   
• Your PC will alert you that it has found new hardware, installs the software and let you know when the hardware is installed and ready for use.

You should see it in the list of network adapters, now without an exclamation mark on it.We have found that many Microsoft Updates, unusual power issues and the like will make this occur, unusually often on Dell laptops equipped with the Broadcom 57XX Ethernet adapter. We suggest if this happens regularly you ask Dell how to fix it, since they sold you the computer, though you should go to their support site and see if there is an update for your PC that addresses it first.We found this link to a new driver posted on July 28, 2006. We do not recommend using this link, but rather you go through your PC manufacturer to get their "approved" driver.