Follow the instructions here:
http://support.microsoft.com/kb/935791#Method3
"Bill Walsh" <> wrote in message
news:4d1e486c$0$18662$...
>I have an Acer computer about 2 years old, running vista home premium
>service pack 1. I'm trying to download and install service pack2 but
>nothing happens after the install command except Windows defender scanning
>the download. Has this download
> been removed or discontinued by Microsoft? I don't want to buy Windows 7
> if I don't have to. also, when I open "Skype" there comes a message about
> a missing part of webcomn.dll. I downloaded the webcomn.dll and dragged it
> into System32 folder but nothing changes. Any information greatly
> appreciated. BW