i have a sony vaio Pcv rs704 with a recurrent problem with sound everything works normally then sound disappears , every type of sound cd , music file , system sounds . If i turn up the volume from the keyboard I can hear speaker hiss , so the speakers are working , also Itunes won't play at all ie the any music files won't run ( even though no sound , the progress indicator for file playing doesn't move ) while this sound problem persists . I can usually fix the problem with a reboot at which point system sounds return as the computer goes into shutdown so I think it might be a software conflict ,though this fault has persisted after several system reinstallations
