PrevX apologizes - Windows Black Screen Root Cause blog posted
From PrevX blog:
The issue appears to be related to a characteristic of the Windows Registry related to the storage of string data. In parsing the Shell value in the registry, Windows requires a null terminated "REG_SZ" string. However, if malware or indeed any other program modifies the shell entry to not include null terminating characters, the shell will no longer load properly, resulting in the infamous Black Screen with the PC showing only the My Computer folder.
Having narrowed down a specific trigger for this condition we've done quite a bit of testing and re-testing on the recent Windows patches including KB976098 and KB915597 as referred to in our previous blog. Since more specifically narrowing down the cause we have been able to exonerate these patches from being a contributory factor.
We apologize to Microsoft for any inconvenience our blog may have caused. This has been a challenging issue to identify. Users who have the black screen issue referred to can still safely use our free fix tool to restore their desktop icons and task bar.
Complete blog entry in http://www.prevx.com/blog/141/Windows-Black-Screen-Root-Cause.html
Thanks to Daniel (Triple Helix for the above). Discussion in http://www.calendarofupdates.com/updates/index.php?showtopic=25584
Update: MSRC on the above issue:
We’ve conducted a comprehensive review of the November Security Updates, the Windows Malicious Software Removal Tool, and the non-security updates we released through Windows Update in November. That investigation has shown that none of these updates make any changes to the permissions in the registry. Thus, we don’t believe the updates are related to the “black screen” behavior described in these reports.
We’ve also checked with our worldwide Customer Service and Support organization, and they’ve told us they’re not seeing “black screen” behavior as a broad customer issue. Because these reports were not brought to us directly, it’s impossible to know conclusively what might be causing a “black screen” in those limited instances where customers have seen it. However, we do know that “black screen” behavior is associated with some malware families such as Daonol.
http://blogs.technet.com/msrc/archive/2009/12/01/reports-of-issues-with-november-security-updates.aspx