It looks like at least some of those that got their hands on the Vista SP1 update one way or another got a bit more than they bargained for, with DailyTech reporting that the update process wreaked some considerable havoc on some users' PCs. Specifically, the SP1 update process took it upon itself to automatically a prerequisite Windows Update, which apparently caused some folks' PCs to dive into an "unbootable loop," the only solution to which is a complete system restore. For its part, Microsoft has now pulled the prerequisite update in question (which apparently means it wasn't much of a "prerequisite"), although that'll likely be of little consolation to those that have already seen their PC put through the ringer.