IIS stops responding after MS05-051

If you having problem with IIS after installing the recent MS05-051 patches, you need to restore the default permission of the COM+ catalog. I should have cover this earlier, I mean COM+ is closely related to the overall functionality of IIS, without it - IIS will not start. Here's couple of symptoms that you may see after deploying the fixes:

• The Windows Installer service may not start.
• The Windows Firewall Service may not start. 
• The Network Connections folder is empty.
• The Windows Update Web site may incorrectly recommend that you change the Userdata persistence setting in Microsoft Internet Explorer. 
• Active Server Pages (ASP) pages that are running on Microsoft Internet Information Services (IIS) return an “HTTP 500 – Internal Server Error” error message. 
• The Microsoft COM+ EventSystem service will not start.
• COM+ applications will not start. 
• The computers node in the Microsoft Component Services Microsoft Management Console (MMC) tree will not expand.
• Authenticated users cannot log on, and a blank screen appears after the users apply the October Security Updates.

More detail can be found in this kb:
909444 Systems that have changed the default Access Control List permissions on the %windir%\registration directory may experience various problems after you install the Microsoft Security Bulletin MS05-051 for COM+ and MS DTC.