My problem only started about 2 weeks ago . Before that I could directly play any video that was on Youtube or any video embedded in an internet download. Now the video plays, in the sense that I have sound and the elapsed-time bar moves along the bottom of the screen, but there is no video picture, just a full green screen. This applies to any video on Youtube or embedded in an internet download. I can still play any video that I have previously downloaded to my PC, be it Flash Video file or MP4 file. The players installed on my PC are the latest versions of Windows Media Player, VLC Media Player, Media Player Classic and Adobe Flash Player. The problem started at about the same time there was a major upgrade to my Avast free antivirus program (to version 8.0.1482) but this is probably a red herring, as I find it hard to believe that could have anything to do with the problem. I have also tried on Internet Explorer and the problem is just the same, so it is not Firefox specific. Can anyone offer a solution? Regards, Barry