Venetian Spy

Ok so I'm trying to watch videos on the internet that are WMV and open with Windows media player. The video keeps freezing on different frames, yet the audio keeps playing! I clicked on its properties and it says that it's video codec is Windows Media Video 9! Please help me, I really need to watch these videos, it's for school and they're important!
I tried downloading codecs but they don't work, and I tried adjusting video card, but it doesnt let me!