internal links stopped working

Whoa, all of a sudden all the internal links to my own website stopped working, giving an error as if the files are not there. Permalinks, Categories, “Read the rest of this entry” etc, none of it is working.

But still, if I go into admin, I can actually find and edit all of my old archived articles, but even if I re-publish them they do not appear on my website. Anyone have any idea what might be going on and how to rectify it? I’ve asked my ISP and so far they seem baffled. Check it out at:
http://www.robwipond.com