Usually this is because a safety thermal cut out has tripped and is preventing your heater elements receiving power.
To cure you need to find where your heater elements are housed and with the power off and plug removed from the wall (saftey first) see if you can find a thermal cutout switch somewhere near the heaters. it will be a small item around and inch square and will probably have some kind of reset button on it. press this until it "clicks" and the chances are it's reset.
Always be careful when doing this - as it may have tripped for a reason, e.g make sure the vents and air intakes are clear as this will have overheated the machine.
Remember: Safety first! if you are not sure of any of this then talk to an approved repairer.
Becks, March 2010
