If you can't Update Firefox to the latest release from within Firefox:

Go to www.mozilla.org or http://www.mozilla.org/en-US/products/download.html and click the green button to download the Firefox for Desktop installer to your computer. Next, close Firefox and run the Firefox Setup 14.0.1.exe file you saved. (no need to uninstall Firefox ahead of time, as long as you never changed the program installation directory to a custom location) ... EDIT : ... but for best results, do a clean reinstall by removing the Firefox program files before installing Firefox 14.0.1. Ref: How to install Firefox on Windows

If you downgraded Flash, upgrade back to Flash 11.4 r402 which is the latest secure version and see these pages for other suggestions:

• Flash Plugin - Keep it up to date and troubleshoot problems
• http://kb.mozillazine.org/Flash#Troubleshooting

I have the same problem. It all startet about one month ago with a Flash Player update. It discontinued yesterday, after an Adobe Air update, but started again after another Adobe Flash Player update. All this while using Firefox 14.0.1 in Romanian

If there are problems with updating then best is to download the full version and uninstall the currently installed version and delete the Firefox program folder to remove any leftover files if there are still problems.

• http://kb.mozillazine.org/Installation_directory

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 14.0.x: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Thanks for the help Guys, uninstalling and reinstalling firefox and upgrading flash resolved all the issues, so turning it off and on again! ha ha thanks again

Problem persists eaven after the following steps have been taken: 1. uninstall firefox (14.0.1 - Romanian) 2. uninstall flash player&plugin 3. restart computer 4. install firefox (15.0 - Romanian) 5. instal flash player&plugin

That is: Youtube works, but other videos and some sites that use flash a animation and live streaming (such as www.antena3.ro/live.php) don't.

ES_Vic, You can look here for other solutions:

• http://kb.mozillazine.org/Flash#Troubleshooting
• Flash Plugin - Keep it up to date and troubleshoot problems (under Troubleshooting) Link: https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems
• Fix common audio and video issues (under Other solutions) Link: https://support.mozilla.org/kb/fix-common-audio-and-video-issues

If you need more help it would be better to ask a new question since this one is now marked "solved" and other contributors may not reply to solved threads. You can use this link as a starting point: https://support.mozilla.org/questions/new

PROBLEM SOLVED IN MY CASE

Hello All, had the same problem like many of the people. After an upgrade, adobe flash player didn't work any more on many sites, including some videos on youtube. The thing is, some of the videos work on youtube, some others don't work. I have tried all possible solutions as described above, but the final approach made things work. My laptop, a Dell Studio XPS L502X has an NVIDIA display card. I resolved the problem by going to the NVIDIA control panel from the configuration panel of Windows. Then go to "Manage 3D settings". In the programs settings tab, search for Firefox. Then choose another graphics card than then the NVIDIA High performance processor.

This will resolve the problem.

-My flash player works everywhere(80%) ONLY ON YOUTUBE NOT. Before this error my videos slow to start(run loading circle symbol)but work constatntly.Not installed realplayer.

- I did not change my configuration,firefox automatice update from 9.0 to latest,but the day of symptom firefox not change.My Flash 11.1r10.

-1 thing i did before flash error: I disabled the orange youtube flash update alerts below the youtube window.(press X)

After the videos not started,the thumbnail images are loaded,i see the full movie but NOT START.

facebook,blogspot 80%OK(not enough),BUT YOUTUBE total dead.

I tried: -delete cookies and all webtemp NOT WORK -block cookies:NOT WORK -uninstall,then old firefox old falsh : NOT WORK -uninstall,manual remove from registration all firefox and flashplayer content then install old firefox old flash: THE FIRST YOUTUBE VIDEO OK(not loadtime,immediately start)

OH MY GOD,NOW(when i write this post)AT THIS MOMENT I REMEMBERED THE ANTIVIRUS AND I WAS BACK THE SECURITY LEVEL TO NORMAL.......(before i not change but I knew that he had caused the flash slow start)

!!!!!!AND ALL VIDEO RUN!!!!!!! and immediately start.

firefoxhelp0101

If you are still having problems with YouTube videos. ou can look here for solutions:

• http://kb.mozillazine.org/Flash#Troubleshooting
• Flash Plugin - Keep it up to date and troubleshoot problems (under Troubleshooting) Link: https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems
• Fix common audio and video issues (under Other solutions) Link: https://support.mozilla.org/kb/fix-common-audio-and-video-issues

If you need more help it would be better to ask a new question since this one is now marked "solved" and other contributors may not reply to solved threads. You can use this link as a starting point: https://support.mozilla.org/questions/new