When you right click on the desktop and click on Gadgets
, does it have more than one page available at the top right? It might be listed on the second page if so.
You might also look in the Start Menu - All Programs area to see if a shortcut to open the Norton gadget may be in a Norton folder there.
If not, then you might be able to just reinstall Norton on top of itself to do a repair install of it, instead of a full clean install of it, to get the gadget back.
Hope this helps,