When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site. Note: this is likely to log you out, so finish up whatever you are working on first. 1. Clear Firefox's Cache orange Firefox button ''or'' Tools menu > Options > Advanced On the Network mini-tab > Offline Storage : "Clear Now" 2. If needed, delete the site's cookies here While viewing a page on the site, right-click and choose View Page Info > Security > "View Cookies" Then try reloading the page. Does that help? --- Some sites appear to be incompatible with Firefox 5. The difficulty is tracking down the problem. To see whether it is caused by the new stricter HTML parser in Firefox 4+, you can turn that off. Please save any unfinished work first. (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful. (2) In the filter box, type or paste '''html5''' and pause while the list is filtered (3) Double-click '''html5.parser.enable''' to toggle it to false (it should turn bold). Then return to the problem page, reload and try again. Does that make any difference? --- Here's the process to roll back if needed: First, I recommend backing up your Firefox settings in case something goes wrong. See [https://support.mozilla.com/en-US/kb/Backing+up+your+information Backing up your information]. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.) Next, download and save Firefox 3.6 to your desktop for future installation. http://www.mozilla.com/firefox/all-older Close Firefox 5. You could install Firefox 3.6 over it (many have reported success) or you could uninstall Firefox first. If you uninstall, do not remove your personal data and settings, just the program. Unless you have installed an incompatible add-on, Firefox 3.6 should pick up where you left off. If there are serious issues, please post back with details.