When I try playing a dvd with WMP10 it seems to be using a 3rd party codec which is now prompting me to register. How do I revert back to the original codec that comes with Microsoft? Anyway I am assuming there are several different codecs for each filetype on my system now. Surely there has to be a way to choose which codec to use to play the various types of files right? So how do I choose say... which codec to use to play .avi files and likewise for dvd?