Licurg: Link's not loading. "Page cannot be displayed"
Open a prompt (start->run->cmd) and run the following two commands
ping secure.square-enix.com
and
tracert secure.square-enix.com
Ping should show if she can get a reply from the server. If ping replies but the browser does not, it's a problem with the browser. If ping doesn't reply, tracert should attempt to show the route needed to reach secure.square-enix.com, and thus (hopefully) help identify where the problem lies. It would probably need someone in a similar location (or even better, with the same ISP) to compare the route with, but let's see first if ping replies.
Edit: Before attempting pings and traces, she did turn it off and on again, right? It is possible that some update is messing with the browser.