Well, normally you install codec packs (like Klite codec pack, Ace mega codec pack,etc)
I would recommend Klite.
Some codecs have a little settings program, or an editable file in which U can change settings.
Look in Program files what codec pack U have installed, or if you haven't got any, install Klite pack (google it, download and install)
Enter the installation folder of the codec pack, and look for an editable file or an exe.
Usually U can enable/disable codecs from there.