In your main.css, you have the links set to text-decoration: underline. Since the menus use links, they are underlined as well. You will need to change these two lines of your css file:
.link { font: 10px/14px Verdana, Arial, Helvetica, sans-serif; color: #ffffff; text-decoration: underline; font-weight:bold; }
.link:hover { font: 10px/14px Verdana, Arial, Helvetica, sans-serif; color: #cccccc; text-decoration: underline; font-weight:bold; }
to look like this:
.link { font: 10px/14px Verdana, Arial, Helvetica, sans-serif; color: #ffffff; text-decoration: none; font-weight:bold; }
.link:hover { font: 10px/14px Verdana, Arial, Helvetica, sans-serif; color: #cccccc; text-decoration: none; font-weight:bold; }
I'm not sure what you mean by having a line above the menu. Are you referring to the space between the menu and the header?