I have been using PREMIERE ELEMENTS 14 with no problems on an HP 55-276na desktop, i7-6700, Win 10 64-bit with 16GB RAM. I copy video recorded at church which is saved as an mp4, upload it and then edit with Elements. Recently upgraded to version 15 but now when I 'add media' the video plays as expected, but there is no sound. If I simply play the file using media player (or similar) the sound is clear.
Have you tried converting the audio file to a WAV?
Tried that without success. Have added a new sound card and it seems to be working now.