open the control panel/system/hardware/device manager, scroll down to "Sound, video and game controllers" click the plus sign, then make sure that the audio device drivers are installed for your hadware, and/or that there are no warnings/exclamation marks next to the audio devices. If there are any marks next to the audio controller on your system, try another driver. If none, go back to the control panel window, open sound and audio devices, then look in the audio tab, make sure that the default device for sound playback is the same device listed in the device manager... I have not tried this driver, and have not downloaded from this source, so use at your own risk, but this driver version has been reported to work with the dell 910 http://www.realtek.com.tw/downloads/