[header] How to install a pci card [title] Unplug your computer. [step] Power down your computer and then unplug the power cable and all the other cables that are connected to the back. If you were recently using your computer, wait a few minutes for it to cool before proceeding. 
[substeps] Note: some pci cards may require you to install drivers before installing the card, but these are rare. Always read the card's documentation before installing.