I checked out some sites to add the codec but it still doesn't work
I could not find it either
A.Hero, if you're still there or anyone having the same problem:
right click the file
then choose "save target as"
save it to your desktop
Then right click on the file on your desktop and choose "open with"
then choose "QUicktime"
Then the file will play on quicktime
If you don't have quicktime, download it from the apple computer site (I believe)