whats wrong with my worcester 35CDi II boiler?

My worcester 35 CDi II boiler(which is installed in my attic), stopped responding to the control panel in my kitchen. it now runs constantly!! even if though control panel says that it is off!! Any info greatly appreciated, as our third child is due and 2 weeks!! And would love to have this problem sorted as fast (and as inexpensively as possible)