IE7 may exit unexpectedly when multiple tabs are open, and you close a tab that contains a non-HTML file
This problem occurs when the Yahoo! toolbar is installed, and the version of the toolbar is between 22.214.171.124 and 126.96.36.199.
To resolve this problem, install the following security updates:
• MS07-016: Cumulative security update for Internet Explorer
• MS07-027: Cumulative security update for Internet Explorer