If experienced problem after installing the security update KB908531 (MS06-015), try below possible solution as per MSRC:
– (If you have multiple user accounts set up) Log onto the computer using an account with Administrator privileges
– Click the Start button, then click Run and type “regedit” at the prompt, without the quotes; this will start Registry Editor
– Locate the HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionShell ExtensionsCached key in Registry Editor
– Right click on the key and select New / DWORD Value
– Rename the resulting value “{A4DF5659-0801-4A60-9607-1C48695EFDA9}{000214E6-0000-0000-C000-000000000046} 0x401”, without the quotes
– Right click the value, select Modify, and type “1” into the Value Data field
– Close Registry Editor
They are working on Knowledge Base
More in http://blogs.technet.com/msrc/archive/2006/04/15/425311.aspx