when i opted for inspect element....this is what i got.....
Opera has modified script or content on www.youtube.com (PATCH-1164, YouTube force Flash player for HTML5 content). See browser.js for details

its not working mozila as well.... but it works in chrome..
everything in my pc is up to date... java...flash player...opera..
re installed opera.....but its not working for the last 3 days....

its something to do with http and html5.....