Help - after import, video no longer has associated audio?

I am trying to import a video with sound that is of the file format (.mp4). It is around 18 minutes long and of a large file size. I imported the video, but no audio file showed up underneath it like they usually do. I was patient and waited a while for the audio file to show up, but nothing. If I play it using windows media player, I am able to hear the audio. However, when I import it into Premiere Elements 15, there is no audio file at all. Is there something I am doing wrong? I couldn't seem to find help on this anywhere else, so I apologize if it is indeed a repost, but I googled it and nothing came up. Thank you!