So when I download AVI. videos they play great, but there is no audio. Actually there is audio for about .5 seconds. Someone suggested I try downloading the DivX player which I did with the same result. Mpegs are fine. I'm using a Mac tower G4 running OS10.3.9 Someone else said that it was a codec problem and sent me to this site. So I looked around and got totally confused. Does anyone know what I need and if so what do I do with it. Sadly I don't even know what a codec is.........Thanks

Try VideoLAN player. It plays almost everything and there is a version available for the Mac.