We’ve been getting some calls from customers who are having some issues with Internet Explorer because of some changes made to an older version of the Yahoo! Toolbar (versions7.0.3 - 7.0.10). Yahoo! have confirmed that this is a known issue and
have guidance available on their website
and via Yahoo! customer support. Guidance is to uninstall the old Yahoo! toolbar and restart your browser. You can then upgrade to the new Y! Toolbar which is not affected by this issue and is available for download at us.toolbar.yahoo.com.