my wife and I are both in our 70s, we accidentally hit shortcut keys, and have no idea how to get back. We do not need those keys ever., and it costs us hours trying to figure out what we have done.
To modify or delete a shortcut key go to Tools > Customize > Keyboard tab. Select the key you want delete and press the Delete button. You must do that in each module you use and for each key you want remove.