To remove a video from your Amazon listing, you must login to your Seller Central Account and then go to the Upload & Manage Videos page. Select the video you want to remove and then click on the Delete button. Take note that this option removes the videos from all the product pages.
You can also delete a video by removing the ASINs associated with it. To do this, go to the Upload & Manage Videos page and then look for the product video. Click on the Manage button then remove the ASINs before saving. Keep in mind that at least one ASIN must be associated with each video for it to show on your listing.