Strange problem this,
Service Pack can be a bit funny with showing up in Windows Update, you usually need to have literally all the updates installed before it shows. But on my setup, there are two nVidia updates (which are outdated!) that need to be installed before SP2 shows.
I know this because I have had to install them before to get SP2 to show.
One of them is a networking controller driver update (from August 2008!) and the other a Forceware driver from April 2009, both horribly outdated.
Unless I install these, Service Pack 2 doesn't show. Why? I do not want to install them, I've got the latest nForce and Forceware drivers so I don't want outdated drivers which are pointless.
Google doesn't show any results on it either.
I suppose I will have to download it directly from the download center.
Anyway, if I was a noob, I shouldn't have to go through it manually should I?