Is it the condensate pipe?

Have 28i junior bosch boiler. Had frozen condensate pipe but literally over 10 kettles later, 5 hot water bottles and 2 hrs of hairdrying still didn't work. Boiler goes on for about 1 min green light stays on if hot water running but nothin happening to radiators then all goes off. Wee green light in middle ( overdrive I think) never comes on. Pressure dropped from 2 to 1 and a half. Its not been below freezing here for at least 2 days. Any suggestions. The boiler is 2 yrs old

mairi
January 2010