Technika tv Why can't I get anything from tv except some coloured bars?

TV broken. Sounds like a screen fault. Technika is Tesco's own cheap Chinese brand. They are in effect the manufacturer, so any warranty issues go straight back to the store. Get your receipt/credit card bill and tell them it's broken. There's some European legislation that gives consumers rights beyond the 1 year warranty period. The TV should be capable of operating for up to 6 years.