I actually saw this problem myself just the other day, but didn't know that it came from the stealth update before seeing this article. Ironically, I had actually convinced my parents to buy a legitimate copy of Windows XP Pro. They were using the infamous Corporate Edition, and I was tired of having to work around the product key changes and other bullshit like WGA, plus every time it came to install updates they would whine to me because they forgot what not to install (WGA). I did a repair install so they could keep all their programs and settings. After that, no updates would install. The help on the Windows Update site actually suggested the same fix to the problem explained in the linked articles (and it works).
Anyway, I am royally pissed off at Microsoft because the move from a bootleg install to a legitimate one broke Windows because of Microsoft's malice and stupidity. Fuck you, Bill. This is how you repay me for going legit? I have already tried a move to Ubuntu (bad support for laptop docking stations, funky video settings, and wireless networks) and Mac (way too restrictive, few hardware choices), but maybe I should try again. I already have Debian on my file and backup servers, plus Ubuntu on my test-bed computer. Microsoft does not deserve any more of my money.