When menu links stop working…

Greetings, brand new user here; sailing along with my first site, all’s well, looks great…when suddenly the Parent-page menu items stop working. The cursor changes as if they will, and I can open them in new tabs or pages by right-clicking…but not directly. They definitely WERE working an hour ago, and all I did was add a few new child pages and fiddle with a few colors…

First, is this likely to be a theme problem, or a WP one? I’m using a purchased theme (Carbon by Nick Cates), and my site is here:

http://www.boxwoodschool.com

ANY ideas, tips, suggestions, REALLY appreciated!

Thanks!
dpc