NFusion reacts that way when there is a big ECM going on or on weekends when they update the servers. I have an Nfusion since several months ago, and it should not last for more than one hour. Then you will have great picture.
If you are not connected to the Internet, in 15 seconds the message that the service is not available appears.
Nfusion is up 99% of the time, ocasionally you get freezing, but as I said, it doesnt last long.
If you had normal picture and now are experiencing freezing, just wait.
If it repeats, as they say above, turn emu of; check that you have a crossover network cable connected ($10 bucks at any radioshack) check that your Internet service is up.
One tip, turn emu on and go to music channels such as Sirus. If they are ok, then its an update from the servers just wait.
Remember, for TV Emu must be off. For music channels, Emu must be on.