The meaning of PCI sound card is simply a sound card installed in a PCI socket on your motherboard. What wombat means is simply does your motherboard use built in sound card or is it an add-on card mounted to a PCI slot on your motherboard.

If it is a built in sound device then the sound drivers can be located on a CD that contains other drivers for your motherboard...

If it is an add-on card then you must determine what manufaturer built the card and what model number it is and then go to that manufacturer's website and get the drivers there or on a cd for installation of that particular sound card.

As it is apparent that you didn't build the computer yourself then I assume it is a major brand such as Dell or HP or Gateway... If so then it could be possible4 that the drivers you need can be found at their website under support/downloads with/by the model number of your computer.
If so download the driver file for the sound card to your desktop so it is easy to find...close out all internet/windows and then install the driver with no programs of any kind running.