I'm not sure - in fact, this is the first time I've seen a page not displaying due to the hack. The other ones we've seen around here have made all the text on the page italic. What that hack does is puts a bunch of spammy code (payday loans, viagra ads, ugh, etc.) right at the top of the page under the body tag. If you use View Source in a browser - you'll see the code of the page -- look for the body tag and just under that you'll see what I'm talking about. (We don't copy spam code here...so that's why I'm just telling your where to look.) So anyway, in this case, the code they added must be causing a code error in Firefox that's preventing the rest of the page from displaying.
It's crappy, stupid and annoying that people do this kind of thing -- sorry you're having to deal with it. You should also notify GoDaddy (though they definitely know about it but should know full extent).