The first step in reinstalling your computer's sound card is opening the system unit. Touch the metal casing surrounding the jack where the power cord plugs in so that you are grounded. Next, locate the position of the sound card in your computer, and unplug any cables or devices attached to it.
Check whether there is a cable connecting the sound card to the CD drive. If it's present, disconnect it. Remove any screws or hooks holding the sound card in place. Next, carefully pull the sound card out of its slot.
Gently place the new sound card on top of the empty expansion slot. Line up the pins on the sound card with the expansion slot, and gently push the card down until it fits in the slot. If the card doesn't go all the way in, pull it out, ensure you align its pins well with the pins in the slot, and push it back in. If you unplugged a wire connecting the sound card to the CD drive, reconnect it.
Screw the sound card onto the frame of the CPU. Close the computer case, screwing in the appropriate bolts to hold it in place. Plug the computer to a power source, turn it on, and install the drivers for the new sound card.