Use this procedure for creating a menu item that does not link anywhere. To add a page to the menu, edit the page and assign it to the primary menu in the "Menu Options" section.
1) Log in.
2) Click on "Add a Menu Item" in the "Quick Links" menu or go to Add a Menu Item (admin/build/menu/item/add/2).
3) Enter the title and description (optional) of the menu item. Enter the character "#" (no quotes) in the "Path" field.
4) Select "Primary Links" in the "Parent Item" field (this will probably be the default)..
5) Assign a weight to determine where in the menu the link will be displayed.
6) Click "Submit".