The best thing to do would be to call Microsoft Support.
Any problem resulting from the installation of a Critical Update is entitled to free support from Microsoft.
Microsoft Security Product Support Policy
Technical support is available from Microsoft Product Support
Services at 1-866-PC SAFETY (1-866-727-2338). There is no charge for support calls associated with security updates.
International customers can get support from their local Microsoft
subsidiaries. Phone numbers for international support can be found