"Broken" means what? You see a wide crack in the video picture? Did it work before? What did you do to "break" it? Does the problem occur with all kinds of content or only certain clips?
Plugins are kept in "plugins" subdirectories in Program Files\Internet Explorer and Program Files\Mozill Firefox. The WMP plugins are called npwmsdrm.dll, npdsplay.dll and npdrmv2.dll. Feel free do overwrite them with a fresh copies from Program Files\Windows Media Player