With a built-in RJ-45 Ethernet port, the Dell C521 desktop computer quickly connects to most broadband modems or wired routers. However, if you have a wireless network and want to connect your C521 system, you will need to install an add-on PCI adaptor. Like most desktop computers, the C521 does not include a wireless network adaptor as standard equipment. Nevertheless, if you want to add wireless connectivity to your Dell C521, you can do so in a few minutes.
Purchase a PCI wireless card for the C521 desktop computer. Virtually all PCI wireless cards are compatible with the C521, as long as they have drivers that support the operating system you are using.
Power off the C521 computer. Remove all cables and peripherals from the computer and disconnect the power cord. Place the computer on a flat work surface.
Use the Phillips #2 screwdriver to remove the two retaining screws that secure the right-side access panel. Slide the access panel off of the computer case.
Slide the anti-static wrist strap on to your wrist. Clip the other end of the strap to a metal surface inside the computer case.
Locate the white PCI slot on the C521 motherboard. Use the screwdriver to remove the screw that secures the metal bracket directly behind the PCI slot. Remove the bracket and set it aside.
Insert the PCI wireless card into the PCI slot. Ensure the card goes into the slot until firmly seated. Use the screw you removed from the metal bracket to secure the wireless card to the chassis.
Replace the access cover on the C521 case. Reinsert and tighten the retaining screws to secure the access cover.
Screw the antenna onto the terminal of the rear of the PCI wireless card.
Place the Dell C521 back into its original location. Reconnect all cables, peripherals and the power cord. Turn on the computer and wait for it to boot into Windows.
Wait for Windows to detect the PCI wireless card and configure it for use. If Windows does not configure the card automatically, insert the installation disc for the wireless card and wait follow the prompts to install the drivers for the wireless PCI card. Reboot the computer when prompted to do so.
Click "Start," then "Control Panel." Click the "Network and Sharing Center" link.
Click "Set Up a New Connection or Network." Click the "Set up a New Network" link, then "Next." Follow the prompts to connect to the wireless router or network.