There is a high number of issues related to a new issue called as "Black Screen Of Death", where in customers / users felt that after installing November 2009 updates on windows 7 clients , the desktop gets cleared completely and produces a black screen where users are unable to perform anything and only solution is to rebuild the entire OS.
Microsoft has done extensive testing on high priority and found that none of their November / previous updates were the culprit which are causing this issue. They also found that the issue is caused due to a malware . This malware belongs to Donol family.
you can produce the below statement for the customers and educate customers
“The reports on the so called “Black Screens” was investigated by Microsoft and found to be inaccurate. The company which issued the report has apologized and made a full retraction. Windows 7 security updates was not the cause of the black screens. There is no fix or update necessary for this, but customers should keep their anti-virus software up-to-date as a preventative measure. So far, Microsoft is not seeing an occurrence of this particular issue in our support channels locally.
Hope this helps!