You can see lots of blog posts and discussion on Windows based community forums, the latest Windows patches delivered in November cause BSOD (Black Screen Of Death) on Windows operating systems including Windows 7. Reports say, some changes in Access Control List (ACL) which caused the problems for many Windows users and preventing some software from running properly.

How do you recognize your system got the BSOD problem due to latest Windows Updates installation?

After starting Windows, system appears normal, but as you are logged-in, the screen goes blank except single My Computer Explorer.

Microsoft says:

Microsoft is investigating reports that its latest release of security updates is resulting in system issues for some customers. Once we complete our investigation, we will provide detailed guidance on how to prevent or address these issues.

The issue was first reported by UK Security firm ‘Prevx’. They also introduced a workaround which fixes the issue but not all BSODs.

Prevx says:

The fix is an executable file, will change your Windows registry so that several of the many problems behind the Black Screen is fixed. The company makes no claims that their download will fix all the possible reasons you’re seeing a Black Screen, but, as they say, “Our advice is try our tool first. If it works, great. If it doesn’t you are no worse off.

After about 24Hrs, Microsoft has reported, “The issues as described also do not match any known issues that have been documented in the security bulletins or KB articles.”

By the way, None of my PC have faced such BSOD issue yet. But after playing with fix and doing some R&D, I got “How does Prevx’s fix work?” It sets shell setting back to the default by modifying the value Shell and set explorer.exe. It sounds crazy. What was the problem? If the problem exists really or Is it valid workaround?
Here is Reg Code, patched by Prevx’s fix

Windows Registry Editor Version 5.00 

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
 "Shell"="explorer.exe"

You can save the code with .REG extension using Notepad.

Think again! What was that?

After a day, Prevx said, “We apologize to Microsoft for any inconvenience our blog may have caused.”

– UPDATED 12/02/2009