Cause - Possible sound driver or CMOS corruption
If there is no sound coming from the PC, uninstall the sound drivers. After rebooting the system, re-install the sound drivers using the driver CD that shipped with the unit or download the latest driver from Cybernet. If this does not resolve the problem, clear the CMOS to remove any possible CMOS corruption.
For instructions on clearing the CMOS by model, please see the related articles section.