Here’s what you require! Clicky, download.
First, before you install anything, go into the Control Panel and rip out all media codecs you have installed, including xVid, divX, and VP62.
Next, install FfdShow. It includes everything, stop worrying.
Finally, install Tversity.
Reboot a few times as you go, done.
Poke me if you get stuck, you should have my number.