Thank you Jason,
Replacing the xml file did the job. What I want to edit is the hover drowdown for Product. I have so many categories that the list drops below the bottom of the screen and the last third of the list is not visible. This does not really look good. What I was hoping to do is to keep 'Search' and 'Show all products.'
However I wanted to add one or two more categories to the dropdown, 'New Products,' and 'Discounted Products,' which are two of my categories and perhaps a couple of others. I can leave the left menu for the whole category list.
Would this be a difficult change and do you have any idea how I would go about it?