as mentioned in the subject, the machine is acer aspire e5-532g, os: windows 8.1.
there is no sound from the built-in speakers. they are the default device, and are not muted. i have uninstalled and re-installed the driver several times, used the driver from the resource cd that goes with the notebook, downloaded it from the realtek website and from the acer website, and still no sound. however, if i connect an external speaker (a stereo cd player) it plays the sound.
the notebook is brand new, so obviously i had no time to break it 
any clue, fellows? been struggling with this for 3 days, read tons of forums and still cant figure out whats wrong