Basics to check:
1: Ensure the electrical plug to the boiler is firmly fixed in (they can come loose)
2: Ensure the thermostat on the boiler is ON
3: Turn the thermostat from off to on a few times, if you hear an audible electrical click when turning on and it still doesn't light, most likely the gas vlave has failed. You will need a RGI if this is the case.
Carefree
October 2010