I think I unstalled some weird virus by mistake

[splashpot]

I'm stupid. I'm usualy smart about this kind of thing. About a week ago, I got a popup saying that I need to install flash player to view a website. At the time, I did think it was a little strange because I thought I already had flash player, but I idioticly threw that thought aside and installed it anyways.

Now I can't see sites that require flash player. I could see them before. And I try re-installing the real flash player, but it doesn't work. I even tried uninstalling firefox and reinstalling, but that didn't work. My virus scan doesn't find anything. There are no urgent side-effects. Can I fix this without reformatting?