Check the Security page for information on a zero day Excel exploit under investigation. They posted Microsoft Security Advisory (932553). Communicate the suggested actions ASAP:

Send your home users to the Protect Your PC Web site.

 

Customers who believe they have been attacked should contact their local FBI office or post their complaint on the Internet Fraud Complaint Center Web site. Customers outside the U.S. should contact the national law enforcement agency in their country.

All customers should apply the most recent security updates released by Microsoft to help ensure that their systems are protected from attempted exploitation. Customers who have enabled Automatic Updates will automatically receive all Windows updates. For more information about security updates, visit the Microsoft Security Web site.

We recommend that customers exercise extreme caution when they accept file transfers from both known and unknown sources. For more information about how to help protect your computer while you use MSN Messenger, visit the MSN Messenger Frequently Asked Questions Web site.