Weird font invasion

Hi,
My Mac is being taken over by a weird fraction font. Originally it was confined to my dashboard, which I never use, but it has recently spread to my email program and some websites. I posted this in 'anything goes' a few days ago (didn't realise it was the wrong forum) and some suggested downloading Main Menu or Onyx and cleaning out my font caches. I have downloaded MainMenu and cleaned out my font caches and my system cache but it's still there. I'm worried its a virus. Any suggestions??
I'm working on a MacBook with OSX. It's about 2 years old.
Screen grabs of fonts attached.

Hi - I am the one who suggested the font caches, that usually cures it

No you haven't got a virus, sounds more like a font clash (2 fonts with the same ID)

Have you added any new fonts to fontbook lately, or removed any from Library > Fonts

I don't think so...but I'm not so saavy with that! I do have a LOT of fonts on my computer which I turn on and off with suitcase. anyway to tell if there is a duplicate in my library?