Mine had the same problem it turned out to be a common fault with these; fixed by replacing the thermostats (about £20) they are sold as a pair, they kick in at different temperatures (identified by a coloured spot Make shore you replace like for like) it's probably just one of them that doesn't work but you might as well replace them both at the same time.
To find them you have to remove the heating element/Fan cover on the back of the machine they are round in shape with two wires each. I hope this is helpful, of corse it could be the heating element, so have a look at that as well.
D. M. Dadswell, March 2010
