My Laptop Has Officially Gone Insane

     Click on the image above to see what I see when I access Twitter using Firefox.
     Last night, something happened on Twitter that I've never seen in my 20 years on the internet. I was sitting there reading my feed when suddenly all by itself the values of everything got bloated, then returned to normal, then back to bloated then back to normal then to microfiche size. What you see in the screengrab above is exactly what I see to this day when I'm on Twitter using Firefox. It seems the only browser I've found thus far that shows the page normally is the hated Microsoft Internet Explorer and even then, that browser, seemingly on its own, changed all the default settings so that I can't even use Twitter. When using IE, it's like being gagged and bound to a chair during a huge cocktail party. I can look but I can't interact. On Mozilla, I can interact as long as I can navigate the site in microfiche size.
     I've never seen anything like this in all my years on the internet. If I was hit with a virus, why does it affect only my laptop, only Twitter and only on Firefox? Thoughts, suggestions?
     This morning, I even undertook the extraordinary means of deleting Firefox from my HD then trying to reinstall it through IE, which was a nightmare all its own. As I'd just said, IE took it upon itself to fiddle-fuck with my security settings so that the browser was virtually useless and disabled virtually every site I'd access, including trying to download rival browsers. I had to hunt and peck through the Advanced tab of the Tools option and randomly undo every security default setting that had been changed since I last used it. And even then, Norton kept raising red flags and saying, "DANGER, WILL ROBINSON, DANGER!" every time I tried downloading Firefox on Mozilla's safe website. I had to literally turn off all my firewalls and every antivirus protection I had just to download a fucking browser that, until today, used to be a piece of cake.
     Finally, I was able to redownload Firefox but, as I suspected, it didn't do a fucking bit of good. Twitter still looks like microfiche and it's unusable. Has anyone else ever seen or heard of this happening before? I can't believe I'm the only person using Firefox on Twitter and am able to believe even less that I'm the only one that somehow got hit with this Rod Serling/David Lynch insanity. Since only Twitter's affected, it's not as if I can change the default settings or fiddle with the default values, so what the fuck is going on? I seem to be the only one on Twitter to whom this has happened but I've never heard of a virus doing this. I've even done a Sophos virus sweep and it found absolutely nothing harmful.
     I'd really appreciate it if anyone can tell me how to make this problem go away. This is seriously pissing me off, largely because Twitter is the only social networking site I use.