Tell me more. Where did you download the IE update from? If it was ATT Yahoo, uninstall it. Browser updates are one of the things you never want to get from a third party. IE updates should only come from Microsoft.

I think I've seen a Yahoo modified version of IE before. You can still start the regular version of IE, but your IE shortcuts probably now point to the Yahoo browser. It's been several years, so I might have the details wrong.

If you want to be sure of having a working browser while you are making your changes, get Firefox installed first before you mess with this.