Indeo 5.1 AVI's no image

My IT guy and I've been messing with this for days. Just added the HP laptop w Vista to my pantheon of PCs and I cannot get my AVIs to play on it. Looked up some fixes online, downloaded the right codecs and they are all where they should be (in system32 folder), then found the fix to get them to play in WMP (had to manually add a file to registry), but still won't open in Quicktime (play the sound but no image). I need to open in QT to convert to MOV files for my various web pages. A LOT of people use indeo 5.1 codec, and I really don't feel like re-recording hundreds of videos in some new software to force them into some new codec. Could someone please tell me how to get my new PC to recognize this codec for QT? I am certain it has something to do with the registry, since that was the problem with WMP, but neither of us knows exactly where or how to add ir50_32.qtx to the registry so the computer can find it.