I was reading this question about Ford's name, and was reminded that it is not his original name. Do we know what his name was before it was "Ford Prefect"?
Sort of, but not really
There's a footnote on this topic in the novel; it doesn't tell us his actual name (though there's a quite compelling reason given for why not), but we do learn that his nickname at school was "Ix":
Ford Prefect's original name is only pronuncible in an obscure Betelgeusian dialect, now virtually extinct since the Great Collapsing Hrung Disaster of Gal./Sid./Year 03758 which wiped out all the old Praxibetel communities on Betelgeuse Seven.
The other kids at school nicknamed him Ix, which in the language of Betelgeuse Five translates as "boy who is not able satisfactorily to explain what a Hrung is, nor why it should choose to collapse on Betelgeuse Seven".
The Hitchhiker's Guide to the Galaxy About Ford Prefect