Just installed Firefox on a fresh installation of Windows 7. Almost all of the text on all pages is displaying in strange ISO, four-numbers-in-a-box characters. For example, this is the login page of Facebook. http://i.imgur.com/OI99a.png Facebook, at least, has some readable text, while most other websites have none. Notes: * Windows 7 Home Premium x64, with Firefox 5.0.1. * Firefox is using Western ISO-8859-1 encoding. Changing the encoding doesn't seem to make a difference. * When I uncheck "allow pages to choose their own fonts", text loads correctly, but (obviously) in the fonts I specified, not the ones that would normally be on those pages. * Pages load fine in Google Chrome. * I have no extensions installed.