1: No sound from earphone or external speaker.

         1.1: Earphone & external speaker works on other devices. --> Contact ASUS service center for help.

         1.2: Earphone & external speaker doesn't work on other devices. --> Contact device manufacturer.

2: No sound from built-in speaker.

         1.1: Turn on the system volume to solve problem.

                1.1.1: Sound available. --> System volume was set to "Volume Mute" mode.

                1.1.2: Sound not available. --> Check whether sound's available by using earphone or external speaker.

                         1.1.2.1: Sound available. --> Contact ASUS service center for help.

                         1.1.2.2: Sound not available. -->Reinstall audio card driver.

                                  1.1.2.2.1: Sound available. --> Audio card driver problem.

                                  1.1.2.2.2: Sound not available. --> Backup the data & Recover the system.

                                         1.1.2.2.2.1: Sound available. --> OS problem.

                                         1.1.2.2.2.2: Sound not available. --> Contact ASUS service center for help.