HELP!! WMM videos won't play having Codec issues

:cryHello
I really have a big problem with Windows Movie Maker. I can't seem to get my converted videos to play in wmm. I hear sound but I can't see the videos. This was the case with all my players like wmp, realplayer. I even downloaded vlc player and the same thing sound but no picture. I had DivX 6codec on my system i got rid of that with k-lite. K-lite seem to fix the problem that I was having initally, which was trying to convert a flv to wmv using SUPER converter and i used tubetilla converter, when ever I converted a flv to wmv it wouldn't play in wmp, realplayer, wmm, vlc player and the player that came with k-lite, i would only get sound but no picture. As I stated downloading k-lite sort of fix the problem only when I logged in as Administrator. Then I could see the pic and hear the sound but only for realplayer and wmp, not the wmm and the k-lite player. I tried to play the 3 videos that come with Vista like the bear, lake and butterfly and the same problem sound but no picture, just a black screen. I downloaded so many codec packages to see which one would fix the problem and nothing worked. I checked to see if it were the converters and no. I checked the players by playing a dvd and it played fine. I download sherlock codec report says no damaged codecs but i'm not sure how to use it. I am fresh out of ideas, unless u smart people can help me. Please let me know or ask any questions. thanks...