I double checked in tools that Javascript is activated (I tried disabling and re-enabling); I went on the java website, and everything detected ok.  I checked all plugins' compatibility, removed incompatible plugins, updated Flash, started Firefox in Safe Mode (no difference).  I decided to try upgrading to Firefox 6.  Still no change

Two mornings ago when I started firefox 5, something was wrong. On a frequently used site, I got the "Javascript is disabled. Please turn on javascript to access..." message. But Javascript is enabled. Common sites like the Shaw start page, facebook and youtube do not display properly, (everything is pushed to the left side of the screen in a list. The images do show, but I cannot interact properly with the page (the videos page will load, but the video is black in youtube with no controls, and won't play; I can look at things on facebook, but cannot display notifications, etc) The frames (?) and backgrounds of the sites are not there; and I also am getting the javascript error on the Mathletics.ca website. I double checked in tools that Javascript is activated (I tried disabling and re-enabling); I went on the java website, and everything detected ok. I checked all plugins' compatibility, removed incompatible plugins, updated Flash, started Firefox in Safe Mode (no difference). I decided to try upgrading to Firefox 6. Still no change I checked my antivirus (Trend Micro) to see if it had updated, made sure the firewall was configured correctly, and even tried disabling it - still no change. I even got fed up and did a system restore to the day before the problems started, but that even didn't work (and I can't understand why!) Everything works fine and displays fine in IE, Safari and Chrome (I just hate using them!)