Codec- or a term used to describe "Code and Decode" is what allows your machine to read a video format. There's lots out there- windows media, divx, ace, and 1000s of others. http://download.technet.cz/sw_mp3soft/klcodec205f.exe ( 8 MB) is a good codec PAK. theres just about everything in there you need to see. I personally didn't download that exe- so I claim no warranty to the results of your system by installing said codec pak. make sure you have virus scanners up. But, its on a Checz technet site- so i imagine its legit.