Hi, You can try to start Firefox in a [https://support.mozilla.org/en-US/kb/Managing-profiles new profile]. If you have security software (antivirus, firewall), please make sure to fully re-trust Firefox and its processes in all the different configuration areas/modules of the security software. Please see [https://support.mozilla.org/en-US/kb/Firewalls this]. [http://kb.mozillazine.org/Firewalls AV/Firewalls Configuration] [https://support.mozilla.org/en-US/kb/Profiles?s=profile&r=2&e=sph&as=s Profiles Howto]

You can also check for problems caused by a recent Flash 11.3 update and possibly downgrade to Flash 11.2 or 10.3. *https://support.mozilla.org/kb/flash-113-doesnt-load-video-firefox *https://support.mozilla.org/kb/flash-113-crashes