Here is our URL: http://bludovedemo.net/guitar101

The top menu is not working on any browsers we have tested on - Safari, Chrome, Firefox.
Every time you click any of the other menus - Contact, How to choose a guitar - it goes to the home page (index.php) instead of going to the actual page it's supposed to go to.

The footer links, however, DO go to the correct pages.

We only altered the CSS in the header / nav area slightly and I already tried taking it out to see if what we added changed anything and it didn't make a difference.

Please advise.
Thank you.