How to Find Out if an Onboard Sound Card Is Not Workingby Stephen Lilley
An onboard sound card is a small computer card that plugs directly into your motherboard. It tells your computer how to process sound information given to it by various programs, including your operating system. A program will send an audio signal to your sound card, which will process it and send it out to your computer's speakers.
Check the Device Manager. Right click on the "My Computer" icon on your desktop and select "Properties." Click on "Device Manager" under the "Hardware" tab to bring up the Device Manager. This is a listing of every piece of hardware your computer currently recognizes. If your sound card has a yellow icon with an exclamation point next to it or isn't listed at all, there is a problem.
Plug a few different devices into your sound card. The inputs on your sound card are located on the back of your computer. You can plug external speakers, microphones and other types of audio devices directly into your sound card from here. If you are having trouble with one device, plug in a few others. If they all don't work, then there is a problem with your sound card.
Check your "Audio" options in the Control Panel. On your computer's Control Panel click on the icon that says "Audio." Make sure none of your speakers are muted. If your speakers are at a regular volume and you still cannot hear any sound, then your sound card is not working.