Remove an audio or video file
After you insert an audio or video file in your Microsoft Expression Blend project, the file is added to the Projects panel and referenced in a MediaElement object on the artboard, and, if you are working in a Windows Presentation Foundation (WPF) project, in a Storyboard.
In the objects view in the Objects and Timeline panel, click the MediaElement object that represents the image, audio, or video file that you want to remove, and then click Delete.
This action removes the media file from your active document. Its timeline is also removed from the storyboard in which it was inserted. The storyboard is not deleted. A pop-up message appears to remind you that if you want to recover the animation timeline, you can undo your last action (CTRL+Z).
If you delete a storyboard without first deleting any audio or video objects that are controlled by the storyboard, the objects will remain in the active document, but will no longer be able to play until you insert the original media files again.
Remove the media file from the artboard using the previous procedure.
In the Projects panel, right-click the name of the media file, and then click Delete. Alternatively, you can click Remove from Project to retain a physical copy of the file in your project directory without building it into your application.