MitsuStyle - No sound on Youtube

Any of you guys fimiliar with this website? Youtube.com? Well, if you are and you know a lot of stuff about computers and the internet then help me out here.

Recently all the sounds for youtube videos has stopped working. Even the sounds on streetfire.net videos don't work anymore for me. My guess is that I am missing a codec but the songs that I have on my computer work and when I play them, I can hear them loud and clear on my computer speakers so I know it couldn't be the speakers.

I've contacted youtube and that's all they told me to do, find their types of codec that would match theirs like mp3 sounds and MPEG-4 codec, which I have dowloaded many of them and it didn't work. Anyone got a solution?