Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

This may be caused by a recent Flash 11.3 update.

See:

• https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems
• https://support.mozilla.org/kb/flash-113-doesnt-load-video-firefox

• http://forums.adobe.com/thread/1018071?tstart=0
• http://blogs.adobe.com/asset/2012/06/inside-flash-player-protected-mode-for-firefox.html

If you can't get Flash 11.3 to work and need to revert to Flash 11.2 then you can download the Flash 11.2 player via this direct link:

• http://fpdownload.macromedia.com/pub/flashplayer/current/licensing/win/install_flash_player_11_plugin_32bit.exe
• http://forums.adobe.com/thread/1022066

You need to uninstall the Flash 11.3 version.

• http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html

I have done all that and still I cannot view youtube videos or the Daily show. this problem persists, it is NOT solved.

I have done all that and I still cannot view youtube videos

NOT solved

What do you mean with using the Modify Headers extension?
Why do you need to make change?

The site seems to work fine for me in Firefox.

• http://www.thedailyshow.com/

You can try to reset Firefox and create a new profile.

• https://support.mozilla.org/kb/reset-firefox-easily-fix-most-problems

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I am in the UK, and cannot otherwise access The Daily Show - unless I do something, - for a while I used Tor but that requires some set up and then I have trouble watching BBC will only allow viewers inside the UK, but then I discovered Modify Headers which allowed me to view The Daily Show without getting that annoying "cannot be viewed in your location". It does not work for Hulu, but works or did work for TDS and Colbert. However, I do not think that is the source of the problem because I tried shutting it off, and - no change. And that would not explain why I cannot seem to watch ANY video on youtube at all. I cannot work out what the problem is.

I have cleared the cache, checked no proxy in the settings, updated both quicktime and adobe flash, checked the plugins update page to see if any udates are available, tried again to play a youtube video and still get "error try again later" clicking the litte red exclamation button gets a " error loading annotations" EVERY TIME. This is new - this behaviour dates to the latest update of Firefox and does not happen in Google Chrome, which I have now set as the default browser until I can solve this problem with Firefox.

the suggestion about unchecking Real Players option of enabling download got me the you tube videos back, now just to find a way to get the Daily show back.