Why does a deleted text appear when playing a video?

Background: I put down the main video clip, and on another video line, I add a text box. Most of the times, the text box works fine, but other times, when I delete a text box, it still appears on the video.. It is like its been embedded on the main video clip? But it will appear for only a second and I do not understand how to delete this. I thought that this might be because when I render, the main video clip has rendered with the text.. but that does not make sense too. Please help.