I upgraded my Ubuntu 12.10 to 13.04 using software updater. After the upgrade Youtube stopped working (both Firefox and Chrome). That is, none of the videos I tried can be played. Progress bar is spinning like video is loading, however after a few minutes "The video is currently unavailable" message appears.
First, I chose HTML5 from youtube settings to fix the issue, but no luck. Then I burned Ubuntu 13.04 to a USB and tried to run the PC from USB to see if there was a problem with the upgrade. I opened Firefox and Youtube played videos with HTML5. After that, I concluded that there was a problem with the upgrade and formatted my PC. However after a fresh install Youtube is still not working.
Is there anyone who knows how to fix this?
Edit: I created a virtual machine running Windows XP using VirtualBox and it too did not play youtube videos.