If you have submitted crash reports then please post the IDs of one or more crash reports that have this format: *bp-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx You can find the IDs of the submitted crash reports on the <i>about:crashes</i> page. *You can open the <b>about:crashes</b> page via the location bar, like you open a website. See: *http://kb.mozillazine.org/Mozilla_Crash_Reporter *https://support.mozilla.org/kb/Mozilla+Crash+Reporter ---- Start Firefox in <u>[[Safe Mode|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 click the Reset button on the Safe mode start window or otherwise make changes. *https://support.mozilla.org/kb/Safe+Mode Try to "disable the hardware acceleration" in the Flash Player. *http://helpx.adobe.com/flash-player/kb/video-playback-issues.html See also: *https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems Flash "Display settings" window: *http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html