If you usually download video files from the internet it may occur that you find yourself unable to play some of the due to the lack of proper codecs. In order to play any multimedia file you download, you´ll need a codec pack that includes all the necessary filters and codecs. Vista Codec Package is one of the most complete codecs packs around.
Once installed, you can enter its configuration panel, though some of its features are for experienced users only. To enter this panel, click on Start -> Programs -> VistaCodecs -> Settings Applications.

A small window divided into tabs will be displayed, each of them corresponding to a specific codec included in the pack.

Last but not least, you can enter another configuration panel for MPEG2 codec only. Follow the same path to enter the panel, but instead of clicking on Settings Applications, click on MPEG2 (default) decoder settings.

In this window you can modify playback colors and other misc settings.
Those are the codec settings you can modify Vista Codec Package. Still, if you´re planning on playing files only, you won´t need to modify anything, just install the package and play your favorite audio and video files.