your boiler has automtic ignition, so no pilot. try turning it off at the mains for a few mins then back on, turn all the thermostats up to maximum and any timers and switches on. if it's still not working then try to re-set the overheat thermostat. it may be on the front panel, usually under a screw on cap. it would look like a small red button with a cross on it. depending on the age of the boiler it amy also be inside, on which case you'd be best to call out an engineer. it really could be any number of things but you can try these ones yourself. if the overheat stat has tripped then still best to get an engineer out to investigate the cause. hope this helps.
Ian
January 2010