Videos not Playing in any browsers

Hello the problem is videos are not playing in any browsers or any sites.I have tried uninstalling and reinstalling flash.also the steps provided in flash player help. but in vain. when i try to access youtube videos the entire screen is blank(white screen) except the url. Sometimes page is loading but an error message is displayed as "An error occured please try again later".initially firefox was down but chrome was able to play videos. But now no browsers can play video.  Please help..

Thanks in advance.