AVIcodec. Al that money and Windows doesn’t come with an MPEG_2 (e.g., DVD decoder) as part of it, so you are reduced to buying various codecs that may or maynot work with Windows.
Right now I’ve found lots of problems with CyberDVD’s codec and lots of oddnesses with the Ligos codec.
Here’s a good site that at least tells you what is the file format exactly you are trying to decode. Its called AVICodec and the output is undecypherable, but detailed.
In terms of “free-codecs”:http://free-codecs.com is a great easy to read list of what codecs are out there as freeware and good explanation of what they do. They also have a bundle of all the free codecs so you can download and them slam onto any machine. This includes an MPEG-2 decoder for instance.