I have had this problem for about 3 months now and am going crazy!
I have called the 'help'line 4 times and they keep saying the problem will be fixed the following day, but obviously this is a separate problem from the one they think it is!
On all the On Demand programmes/channels (ITV Hub, All4, Demand5) the trailer preceding the programme will play, then the screen either goes totally black and freezes, or freezes on the last screenshot.
I have obviously rebooted the box about a million times.
Please can anyone suggest what I can do - the last 'help'line person I spoke to promised to call me the next day to check it was working but did not.
I'm going slowly mad not being able to get to the bottom of this, and if it's not sorted quickly I'm just going straight back to Sky as its not worth this hassle for not being able to watch anything!