Hi @Anonymous User and welcome to the board. 
This sounds very much like it is related to the problems that @Lindzi and others have been having for quite some time now and whilst there isn't a proper "fix" for it, Now TV know about the problem and are supposed to be working on it. You could try the old trick of unplugging your Now TV box, leaving it for a few minutes and plugging it back in, that will re-boot it and you will get an animated "Chattering Teeth" page, followed a few seconds later by the normal Home Page.
Lindzi has been driven bonkers by this and it must be really annoying, she has even tried the NowTV Samsung app on her telly and is still suffering. There are a few threads about it in the "Black Box" section (You don't say which box you are using, so I'm guessing that it's a black one) and it might help to know that some other folk are having the same problem. The strange thing is that it doesn't affect everybody and one train of thought was that it was down to some settings on the "Virgin Hub"....Again, I don't know if you are using one of those, so that's not much help either! ....Sorry! 
As I say, you could try the old disconnect trick but I can't promise that it will work. Now TV really need to have a good look at this as it is affecting and annoying a lot of their customers.
I'm sorry not to be the bearer of glad tidings but I hope that you are having a good Christmas in other ways.
All the best!
