Weird characters in Firefox

I recently had to reinstall Windows XP and along with it all of my programs and since then I have been seeing weird characters in Firefox. They are not everywhere and I can still browse fine for the most part, but it is rather irritating. The symbols don't show up when I view the same pages in IE, and they weren't showing up before the reinstall. I have tried switching to UTF-8 (and just about every other option on the list) and have installed several language support things but nothing has worked. Does anyone know what, if anything, I can do about this? And would it have anything to do with the fact that I went from XP Pro to XP Home? Just curious.

Thanks!