Firefox isn't displaying websites properly
Just recently Firefox started displaying websites (Yahoo, Youtube, and basically anything other than Wikipedia, Google, and Mozilla.com) incorrectly. The sites show up without any banners or formatting, everything appears like the page's site map. On Youtube videos won't play and just navigating on any page is impossible. Everything is just URL's, there is no real layout to the site anymore or buttons to click. Basically each site is just completely messed up. I've tried clearing all of my history including cache and re-installing Firefox.
Operating system
Windows XP (SP 2)