Pounding on the update button in this screenshot does nothing. Nothing is downloaded, installed, etc. No message, nothing at all! Clicking “Release Notes” and “More Information” also does nothing.
Searching for this update yields nothing useful, too. What ever shall I do?

Is Google Chrome your default browser by chance? I see the same behavior in that case, but not when IE or Firefox is. What Wade suggested earlier is precisely the file that pressing that button would have downloaded for you.