Quicktime 7.04 Pro

It is not that QT does not support avi files but that it will not play sound in avi files that have audio encoded with variable bit rate mp3 . Open the avi in QT Player and check MovieInfo (Windows menu) to see if that is the format.
If you have a Video for Windows codec that will play the avi in Windows Media Player you can use this Windows freeware to convert the sound to a QT-friendly format. VirtualDub
Open the video in VirtualDub, set video to Direct Stream Copy in the Video menu. That way the video track will not be modified. Then set the Audio to Full Processor Mode and set the Compression to IMA format. Then use Save as Avi in the File menu to make a new file. Since only the sound is modified this process goes very quickly. The resulting avi should now play the sound in QT.

I saw your message and following response and I too am having problems with QT. I can't even get the picture to come on as well as no sound. I'm really green at this and just started a few monthes ago downloading music from limewire and now I've started doing the same with movies.The files are mp3, mpeg, avi and dvix. Some will play on my media player and some will play on itunes video player but I would like to have them all in QT if I can get them on there in one place. When I try opening a file it freezes everything up and I have to start all over again. Do you know what I'm doing wrong? I would appreciate any help. Thanks Irene