Admin Forum:What Links for "Video:" pages

Hi, I wanted to cleanup every "Video" in my wiki, but whenever I check WhatLinksHere for the video, it sometimes show that it isn't linked anywhere, BUT when I do delete it, it causes red links because it was actually linked somewhere. How can I effectively nit out which pages the Video: is linked to? And if possible, how can I disable "Video:" so that users can only use the tag in my wiki? ~