I think you have blown either the fast blow fuse on the PCB or the 3AMP fuse in the spur to your boiler as the green light just indicates that the boiler is receiving power , if it has gone out a fuse has blown or an RCD has tripped, if after resetting the RCD or replacing the fuse it happens again most likely causes are either the Boilers pump or fan but can be other things so recommend you call in a qualified engineer if it trips again
Ian
April 2010