Hi Linda. We have just had the same problem with our Condeser Hot Point TDC60. First check the filter vents and clean out if you havent already. We had to change the Element as this had burnt out (£42) Easy to replace. Or it may be the Thermostats (£20 approx ) sold in a pair. Very easy to replace. One of ours has a green spot on it, if upon inspection, if it's concaved, it can be reset by dropping it on to the floor till it's not concaved any more. Did'nt find this out till we had the new ones. It worked for me in the end.
Best of luck.
ROB, September 2009