Once in a while, I have this happen to me too. I'm not sure what triggers it, but I can only go to certain sites, but then it will mysteriously clear up.
Sometimes, when I click on an HTML link, it asks me if I want to download/save the HTML file. Weird.
Other times, it will ask me if I want to download the file '
www.example.com' or open it, and what would I like to open it with?