I had a similar problem with my box late last night, managed to get it working again without the Live Pause facility, then decided to try and restore this facility by restarting the box today with no joy.
At this point I used the advice below without success.
Decided to ring SKY to find a fix, the guy gave the same advice as Keith's post, but rather than depressing the up & down buttons, I was told to depress the left & right buttons. I was then asked to wait 2 to 2.5 mins before pressing the "SKY" button on the remote, the green light came back on.
One downside all my recorded programmes have been deleted...hey ho but at least my box is operational once more.
I also asked the guy prior to pressing the "SKY" button how quickly an engineer would be able to replace in the event of the fix not working - he replied "One/Two working days"
Anyway thanks to Keith for placing the original post , as many people can't be bothered once they have found a fix.
John, December 2010