When I open a website or Word document they automatically used a unreadable novelty font that's installed on my machine. I deleted that font and they started using a Dingbat font. It's really weird. On websites that specify a font it always defaults to this weird font. It's driving me nuts.
Remove all fonts you added and things should go back to normal. Basically, remove all fonts from your Hard Drive > Library > Fonts folder and your Home Folder > Library > Fonts folder. Restart and see if everything is back to normal. If so (and it should be), then you were have a font conflict. You probably had a third party font that was using the same identifier as one of the OS X installed fonts. You can slowly replace the removed fonts until the problem reoccurs, then narrow it done to which font or fonts are causing the problem (probably one from some small or unknown company).