Hi Lovelis- The first step I would recommend is to review this help article: http://mzl.la/PMJRIb There are many potential reasons behind slowness, and this article lists many options for you to try- or to at least narrow down the reason behind the change. Hope that helps!

Check the connection settings. *Tools > Options > Advanced > Network : Connection > Settings *https://support.mozilla.org/kb/Options+window+-+Advanced+panel If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly. See "Firefox connection settings": *https://support.mozilla.org/kb/Firefox+cannot+load+websites+but+other+programs+can You can also try to disable IPv6 *http://kb.mozillazine.org/Error_loading_websites You can try to reset (power off/on) the router. You can check the Network tab in the Web Console (Firefox/Tools > Web Developer;Ctrl+Shift+K) to see if that gives any clues about the cause.<br /> You can click an entry to see the response headers and check the Timings tab in the right pane. *https://developer.mozilla.org/en/Tools/Web_Console ---- Note that your System Details List shows that you have a user.js file in the profile folder to initialize some prefs on each start of Firefox. The user.js file is only present if you or other software has created it, so normally it wouldn't be there. you can check its content with a plain text editor if you didn't create this file yourself. The user.js file is read each time you start Firefox and initializes preferences to the value specified in this file, so preferences set via user.js can only be changed temporarily for the current session. *http://kb.mozillazine.org/Preferences_not_saved