See: *http://kb.mozillazine.org/Firefox_crashes *https://support.mozilla.com/kb/Firefox+crashes ---- 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 ---- Create a new profile as a test to check if your current profile is causing the problems.<br /> See "Basic Troubleshooting: Make a new profile": *https://support.mozilla.com/kb/Basic+Troubleshooting#w_8-make-a-new-profile There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems. If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.<br /> See: *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox