Sky HD channels have gone funny

[RosscoPCole]

Just noticed that the HD channels on our Sky have gone green and pixelated. The sound is ok and so are the non-HD channels. I've not moved the tv or the Sky box. Any suggestions?

[_dobbo_]

Turn the power off for 20 seconds then back on, this fixed it when it happened to us.

[RosscoPCole]

Thank you. Should have tried this earlier. If in doubt reset it!