Update: Microsoft has denied Prevx's claims, calling them "inaccurate," among other things. Redmond contacted Prevx who responded with a blog post confirming that Microsoft's recent patch was not to blame. Prevx has apologized for the inconvenience, losing some credibility in the process.
Original story: A Computerworld report suggests that Microsoft's most recent batch of security patches may be causing black screens on some systems. According to Mel Morris, the CEO of security company Prevx, the issue was discovered last week and affects Windows 7, Vista and XP. It supposedly stems from changes Microsoft made to the Access Control List (ACL), which interacts with registry keys to create visible desktop features.
The patch alters those registry entries, and some installed applications simply aren't aware of the change, thus malfunctioning. Morris notes that security applications seem to be particularly affected, and called the bug "massively debilitating," forcing some users to reinstall their operating system. Thankfully, Prevx has provided free software that fixes the registry to match the ACL settings, and that should resolve the issue.
Microsoft has not commented on the issue, and Prevx plans to supply Redmond with a copy of the remedy. Check out Prevx's blog post for more information, or simply download the fix here. If you've experienced this problem, feel free to blow off steam in the comments. In the meantime, if you haven't updated Windows yet, you may want to wait -- or at least keep the fix on-hand.