VLC sound problem

Hello,
I have been using my VLC media player to play video recordings for a project I am working on. Everything has worked great, but suddenly, while listening and watching a video file, the sound stopped playing. I thought it was a problem with the recording at first, but I went back to the part i'd just been listening to and now it has no sound either.
So it seems to be a problem with the media player.
I did already check audio preferences and my S/PDIF box is already unchecked.
My sound on my keyboard is turned all the way up, and the audio isn't muted (at least no check by the "muted" on the audio menu.
I hope someone knows what to do. I'm bewildered!!! Hope someone can help. Thanks in advance!
The files are MTS files but I doubt that that matters. I've always been able to hear the sound on these files before.