XP SP3 hitting Automatic Updates later today
For computer users who follow Microsoft’s advice, Automatic Updates is set to download and install recommended updates as they become available. However, if there is a glitch in the installation process, users could wake up to an unusable computer. That is why I recommend you use Automatic Updates solely to provide a notification of update availability.
At this point, Microsoft knows most of the causes of SP3’s installation and compatibility problems. I believe that Automatic Updates will first scan your computer for the known troublemakers, and if detected, will disallow the download/installation.