Computer components have become more reliable than ever. Although many parts are now integrated onto the motherboard, it may become necessary to add or replace a sound, video, or network card due to component failure or the need for improvement. Integrated components can be left in place, and the problem solved by installing a second card into an available PCI slot. If a component such as a network card fails it can be replaced easily and inexpensively.
WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL. http://www.kitchentablecomputers.com/static.php - rules
Only work inside the computer case when the power has been switched off and disconnected. Never open the power source. Some of the below steps recommend removing physical parts within the computer. While in the computer it is highly recommend that you be aware of ESD and its potential hazards Turn off the computer and inspect the case. Remove the screws that hold on the removable side access panel. Remove the panel and lay the computer on the other side. Locate the network card. Inspect the rear of the computer to locate the network port. If it is a PCI-style card it will be the card with the single connection port on the rear face of the card. If it is a fixed part of the motherboard it will be located near the connectors for the mouse, keyboard, and USB ports. If it's a PCI card, remove the retaining screw and remove the card. Remove the PCI network card if present. Leave the case open and stand the computer back upright. Connect a keyboard, mouse, and monitor and restart it. Open the new network card and remove the installation CD. Insert the CD in the computer and follow the installation instructions. Shut the computer down again after the installation is finished. Lay the computer back down. Install the new network card in any available PCI slot. Replace the case and stand the computer back up. Hook up the keyboard, mouse, monitor, and a network connection. Restart the computer. Accept the default installation settings when the Windows Found New Hardware Wizard launches. Select No on the screen asking you to check for drivers online if it appears. The wizard should continue and find the newly installed drivers. Complete the Found New Hardware Wizard. Reboot the computer even if it does not ask you to. Open Internet Explorer, Firefox, or your favorite browser once the computer is running again. Ensure connectivity by trying several different websites. Hope this helps.