I had the same problem. I unplugged the machine & took off the rear panel (bottom left) to reveal the heating elements. There are two shiny discs attached nearby - these are the thermostats. They should both be convex ("bulging" out) if one is concave then it has been tripped. You can either buy a new kit for £20-£25 or try dropping the concave one/ones you have until they pop back out. Reconnect EXACTLY as they were, power up and test. It worked for me!
Marcus
November 2012