To open your computer case
Turn off your computer and unplug it from its power source. This is very important. Installing a card in a computer that’s plugged in could shock you or damage the card and computer.
Open the computer case. Look on the computer cover (usually on the back) for screws or clasps to undo the case. Computer documentation typically includes instructions on how to open the case.
After opening the case, ground yourself by touching the metal casing that surrounds the jack where the power cord plugs in. This can help protect you from an electric shock and can help protect the new card and existing computer components from static electricity.
To remove an existing sound card
If you have an existing internal sound card, you should remove it before installing the new card. If your computer has a built-in sound processor, you can proceed to the “To install your new sound card” section of this topic.
Locate your sound card. If you’re not certain which card is your sound card, follow the wires from your speakers to the back of the card, and then note which slot that card is in.
Unplug any speaker and microphone cables from the back of the sound card.
If there’s a cable inside your computer connecting the sound card to your CD drive, disconnect it. Many newer computers don’t have this cable, so if it’s not there, you can skip this step.
Remove any screw or hook holding your sound card in place.
Carefully pull the sound card straight out of the slot. Be careful not to twist or bend the card as you remove it.
The card might need one or two gentle up-and-down nudges to come loose. Even if you’re throwing away the old sound card, use caution when removing it to avoid damaging the motherboard. If it seems stuck, it’s better to spend a few extra minutes tugging gently than to rip the card out too quickly.
If you’re not installing a new sound card, install a slot cover if you have one, and replace the screw. Then, close the computer case and replace any screws you removed when opening the case.