I am getting absolutley sick of the endless problems this machine progressively throws up. The latest one is every ten mins the screen goes green with the audio still running. It happens with live tv, video playback and tv portal. Nothing can get rid of it except turning off and on again. Even that failed to work after some time resulting in having to completely re-booting the machine.
The best thing to do is try a different HDMI cable, if you still get the same problem then there maybe a HDMI output fault on the machine. You could also try connecting it via the scart socket and see what happens.