Is this a problem with your DVD player or with Vista? Because AVI and MPEG files are opened by Windows Media Player. Your posting seems to have been corrupted, so it's hard to tell what your problem is.

devil, welcome. We do need to know more about your problem. It sounds like you created some data DVDs under XP using Nero. Now under Vista, what happens? Does the DVD drive recognize the disc and display the files? Do the avi and mpeg files on the DVD not show up, but other file types do? Do the avi and mpeg files show up, but won't play?

My crusade against codec packs is not a mere preference. I STRONGLY RECOMMEND in the MOST EMPHATIC TERMS that everyone should AVOID USING CODEC PACKS EVER! These things are bad, they cause conflicts, and I could explain why but it would take many paragraphs. Let me just say this -- I have fixed many software conflicts that were caused by codec packs. Uninstalling codec packs has restored function for many users with problems. Most of the time, the conflicts occur long after the codec pack is installed, so the user never thinks that it might be the problem. You have all been warned.