If you don't know what soundcard you have, chances are you're using one that's onboard (built into the motherboard). Look at the speaker output, if it's is on the same board as the mouse, keyboard, network inputs then it's an onboard one. Either way you identify the card by opening the case and looking at whatever the speaker output is connected to. Note the model (usually printed directly onto the PCB, sometimes on a little sticker) and google that + xp audio driver.