I would say you definitely have too much money and time on your hands....Jeremy Kyle on a 42" Plasma - must be awesome !
Just kidding....Check the picture on another device (DVD). If it is not catastrophic it is most likely the scart lead connectors. Make sure they are all well pushed in. You can also get 'Scart hang-up' - that's when you have several 'boxes' interconnected, DVD, SAT, VID, GAME, and one of them still has control. You may need to close everyting down (sometimes pulling the plugs as well) then switch things on in order. It can happen with cheapo Digi-Boxes in circuit.
Malcolm X, September 2007