MAC Users - HELP ME PLEASE

I downloaded a avi file earlier today, and tried to play it in Quicktime. The sound wouldn't play, and I thought maybe it was because I hadn't updated that Divx program that everyone seems to use since like 2003. So I download this and install it. File still won't play audio, and now it plays the video in this weird split screen mode. I figure that the file just hates me and delete it.

Now, I go to watch another avi file, one that I have watched before and know works perfectly. I get audio but the screen is just white. I delete everything labeled "divx," programs and preferences and restart the computer.

Now every avi file I try to play looks like ( this )

Does anyone know what the hell I did and how to fix it? I am seriously freaking out here. I'm a vidder. Losing my ability to watch avi files is not something I can live with. Do I need to redownload divx and do something different? I'm desperate.

I'm on an iBook running 10.4.8 and I use Quicktime Pro 7.1.3.

ETA: Fixed. Apparantly the new version of Divx is a giant bucket of shit. I deleted everything with the word "Divx" in it, and then reinstalled the old version. Everything is kosher again. I really did not need my computer to give me a fucking stroke tonight.