Following is a four step guide to finding out what soundcard you have.
1. Go to the start menu and choose run.
2. At the run prompt enter: DxDiag
3. In the DirectX Diagnostic Tool window that appears, click the Sound tab.
4. In the device area you can see the name of your audio card. For audio cards the manufacture is often only a number but the name usually includes the manufacture name as well. Creative, Realtek and VIA are common manufactures.