Over the last couple of days I've had a few websites load with all the text in Earwig Factory font (or a font very like it) and making them unreadable. It seems to be a random selection of webpages and its not limited to just Firefox (my default browser) or Internet Explorer.

Is this a virus? Or something else?

I!m running XP and I've got AVG Anti-virus software running and updated.

Anyone got any ideas?
Thanks