Menu links stopped working – getting 404

Got a new client site all finished and working over the weekend at http://www.francisvalehome.org/. Was working fine today, received input from a form on the site this afternoon. Tonight happened to browse it and the home page comes up but none of the interior pages will load either from the menu or from the WordPress admin. Haven’t changed anything.

Don’t even know where to begin on this one. Please help! I will have an unhappy client in the morning!

Called the hosting company (GoDaddy) and she said the path was wrong because it was looking for folders but I don’t think she is correct. I have the original of the site on my own hosting and the link path is the same and it works over there.

Quite desperateplease help!