my sister has one of these units and of late on hd she has had picture and no sound,
(bit like my house sometimes) well i am normally quite good at electrical units so she asked for help.
tried a new scan , no change tried a factory reset and boy am i stuck ,it will not let me past pin ,no matter what i do , the code i know is 0000 but after that the bottom right corner says next, but when i press ok the delete comes up and pin code gone again and again,
if i leave it disconnected for a few days do you think it will allow me to reset
REALLY could do with help

Firstly, you should not have retuned the box. That is the very last option you should use never ever the first.

The problem could well be how the audio output is set up. If it is just plugged into a TV and not some sort of surround system then the TV might not be able to handle the surround signal some HD channels use. Setting the output to PCM Stereo would likely have cured that.

As for the PIN entry.

Are you sure there is only a NEXT button on the screen? Is there a DELETE or CANCEL button also? Maybe the DELETE/CANCEL button is the default highlighted choice which is being "pressed" when you hit OK? If that is the case then try using the left or right arrow button and see if the NEXT button changes appearance to indicate it is now active. That's about the only reason, short of a fault, I can think of to explain why the code disappears. Unless it has been changed from 0000 and the reset didn't also reset the PIN, which would be a real bummer if that were the case!