sony 40 inch hd lcd tv model KDLW40A12U no picture?

when the tv is switched on the green power light comes on but to the left of this a red light flashes 15 times, stops, then flashes again for 15 seconds and son. i have been told it is a code for an engineer to help determine the fault. the tv is three and a half years old and out of warranty. sony directed me to a company who want £110 to look at with a minimum repair cost of £275 (which iwould include £110 fee for looking at it) depending on what is wrong repair could be hundreds of pounds. does anyone know what might be the problem, or should i just buy a new one!