Thanks for your reply
If it was cable the problem was probably related to your TV but that doesn't necessarily mean that it's faulty. If your neighbour has recently placed a computer or microwave oven on the other side of the wall to your TV, interference from it could cause your picture to break up. It could even occur if he'd put his own TV there. All devices which receive radio signals (such as radios, TVs, digiboxes, PVR recorders, etc) also transmit them. In some cases one device can interfere with reception on another.
Chris