I have made several successful trial movies with Vegas 9, but suddenly the audio track is not being rendered with the video. The audio plays perfectly well in Edit, and I've made sure that I haven't accidentally muted it, but it's just not there when I render an .mpeg. No doubt I've inadvertently changed some setting, but I haven't been able to find what it is. It worked on earlier renderings from the same video/audio. I'm a brand new user and new to video editing, but an old hand at computers and web sites.