.mov problems in Windows Live Movie Maker

I am so frustrated...Windows Live Movie Maker claims to work with .mov files. I am not finding that to be true.
I currently have Vista Home Premium. I was using windows movie maker and windows dvd burner with my standard def videos...that was working fine. Now I have hd video in .mov files (kodak camera), so I downloaded WLMM. At first, the video wouldn't load into the software...I downloaded the windows essentials codec pack (thanks to cnet)...and now the videos will load (and play in windows media player). However, I have now sound...only the video.
I've done some research on this issue and saw that there are others with this problem, but I haven't found any advise that I think is applicable to help me. I do not want to change the .mov files into .wmv (or anything else) because my understanding is that it will greatly downgrade the quality. If WLMM claims to work with .mov files, then why is this such a problem???? I am not all that tech savy (the fact that I was able to even figure out and download the essential codec pack is a big deal for me), so this is a true headache for me. I just want to be able to do some simple editing of my home videos (of my kids) and burn them onto DVD... Please help!!!