Possible reasons why your soundcard is not working:

• Sound Playback Program-specific problems
• Playback device not configured properly
• Mixer settings not configured properly
• Hardware not configured properly
• Defective hardware
• Disconnected cables or plugged in wrong source connection
• Wave sound files are damaged
• Compression-related problems

We suggest utilizing the Microsoft windows knowledge base for detailed information and techniques in troubleshooting soundcard and sound playback issues for your specific Microsoft Windows OS.

Link:
http://search.support.microsoft.com/kb/c.asp?ln=en-us

For Macintosh users we suggest utilizing the apple webpage knowledge base technical support or any of the many macintosh user resources on the web.

Link:
http://www.info.apple.com/siteindex.taf