Video/Audio Playback issues

I am having an issue with the playback of the files I downloaded. The files will download just fine but when I go to open them they are all messed up. If they are a video file they open and look to be playing but the player screen is just gray. If they are an audio file they play but there is no sound. I have checked my volume and nothing is on mute. I have tried downloading all types of files and they all are playing back like this. I am using limewire pro 4.16.2 and my default player is VLC media player. My OS is Windows XP. I have already tried using the limewire media player but VLC seems to override it. Does anyone know how this can be fixed? Thanks