How to install a computer expansion card

Updated: 08/02/2020 by Computer Hope

Many types of expansion cards can be installed in a computer, including sound, video, modem, network, interface card, and others. In many cases, these expansion cards will fit in a slot in the computer called a PCI slot. However, in the case of video cards and a few others, they may fit into other types of slots, like an AGP (accelerated graphics port) slot or a PCI Express slot. Before purchasing and installing an expansion card, make sure you know which slots your computer has available on the motherboard. The picture below is an example of a motherboard with six expansion slots: two PCI Express slots, three PCI slots, and one AGP slot.

Computer motherboard


While working in your computer and with an expansion card, make sure you're aware of ESD (electrostatic discharge) and its potential dangers. We recommend using a grounding strap while working on the inside of the computer.

To install an expansion card, turn off your computer, unplug the power cord from the back of the computer, and remove the side panel from the computer case. You should be able to see the motherboard in the computer case. The expansion card slots are often on the bottom half of the motherboard (see example above).

Find the expansion slot that is of the same type as the expansion card. Remove the metal bracket slot cover on the computer case that corresponds to the expansion or if you're upgrading an older expansion card unscrew and remove the expansion card. If you're replacing an expansion card, remove the old expansion card first.

Handle with care

When handling an expansion card, don't touch the gold plated connectors. Any grease or dirt on these connectors can cause corrosion. It is best to handle expansion cards by the metal back plate.

Internal modem expansion card

Gently insert the expansion card into the slot at a 90-degree vertical angle, making sure the external connectors sticking out through the back of the computer case. Apply a gentle pressure to push the card into the slot completely.

Make sure the expansion card is properly seated and secure the card in place using the locking mechanism on the computer case (screw, plastic or metal locking brackets, etc.).

Plug the power cord into the computer and turn on the computer. Once the computer has loaded into the operating system, install any necessary hardware drivers and software needed for the expansion card to function properly.