I had the exact same issue....outside of RR I could play all the videos in my MPclassic with the k-lite mega codec package. but then when I tried to play them in RR they just wouldn't show up in the playlist. What I did was, read your posts.....got nothing, then wondered if the reason they weren't playing was they were not on the extension list in RR. Well there are too many extensions to list and each one had its own little eccentricities so I just cleared that field in RR. Low and behold everything showed up and all of them play.