Start Firefox in <u>[[Safe Mode]]</u> to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes). *Don't make any changes on the Safe mode start window. *https://support.mozilla.com/kb/Safe+Mode ----- Do a malware check with some malware scanning programs.<br /> You need to scan with all programs because each program detects different malware.<br /> Make sure that you update each program to get the latest version of their databases before doing a scan.<br /><br /> *http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware *http://www.superantispyware.com/ - SuperAntispyware *http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page *http://www.safer-networking.org/en/index.html - Spybot Search & Destroy *http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free See also: *"Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked ----- The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.<br /> You can try to decrease the value of the pref <b>network.http.max-connections</b> from 255 to a more modest setting like 30 as used in Firefox 3 versions. *https://support.mozilla.com/kb/Firefox+never+finishes+loading+certain+websites