Assuming you still have Firefox as a browser (or reinstall if you haven't)), go to Tools , Options, Advanced and you will see an box to make Firefox your default browser. Just select it and it should replace IE.
this has happened to me before and I was able to fix it, but I guess this is another 'Senior Moment' for me and I'm stuck. most of the online suggestions show you how to set the default when you already have Firefox, which I don't.
I am using Windows 7. Thanks, Mike

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