Check you computers BIOS and make sure that the onboard audio device is enabled. To activate the BIOS utility, press <F2> during the POST; while the notebook PC logo is being displayed. If it is, start windows and check in the device manager to make sure it shows your audio device. See if there is an exclamation mark in front of the device and/or it lists any errors. Then reinstall your audio drivers, you can download them [http://us.acer.com/ac/en/US/content/drivers|from here]. Hope this helps, good luck.