Media Sharing Won't Turn On

> I have tried turning on Media Sharing under both Network and Sharing Center
> and WMP 11, but each time after going through all the motions after I click
> "Ok" Media Sharing is still displayed as "Off."
>
> I have attempted to trouble-shoot through Services.msc, but that has not
> made any difference either.
>
> I am able to see my Media Share folder on the computer that it remains "Off"
> on, but the Media Share folder and subsequent media files are invisible to my
> other computers on the network.
>
> Coincidentally, I am unable to download/install the update to Windows Media
> Center for Vista Home Premium and Ultimate in order to add the "Internet TV
> beta" feature on same computer.
>
> I have been searching the internet to try and trouble-shoot this problem for
> days now.
>
> If someone could tell me how to resolve this, I would be VERY grateful. I
> have a ton of music/videos on this particular computer and would like to
> simply share through WMP 11 instead of having to navigate through the network
> to the specific containing folders.