Although Windows recognizes a large amount of file types, there are some extensions that it may have trouble identifying. PreviewConfig is a simple, free application for Windows Vista that allows you to associate a file extension with a specific type of file. That way, if your system doesn't know what to do with .ogg files, you can use PreviewConfig to tell your system that those are multimedia files that can be opened with certain programs. All of this makes Preview Config a useful tool.
