Microsoft Security Bulletin MS07-002 - Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (927198)
http://www.microsoft.com/technet/security/bulletin/MS07-002.mspx

Revision:
V1.1 (January 12, 2007): Bulletin updated Caveats and "What are the known issues that customers may experience when they install this security update?" under the "Frequently Asked Questions (FAQ) Related to This Security Update" section.

Note: No need to reinstall the update if you got it installed already.