Media Sharing with PS3 and WIndows 7

I have searched everyone for how to get the PS3 to media share with WMP12, but mine just isnt working. For some reason my PC cant detect my PS3, under network and sharing>media streaming options my PS3 doesnt come up as an option, why is this?

Same here. It's odd. I did the same method with my Computer with my Sister's and It worked.