Thank you so much. I have done this and it has solved the problem, also sincere thanks to everyone who replied. Is is so kind of you to take the time and trouble and is much appreciated.
I have an optima compact alarm system which has stopped working. It just makes a clicking noise, non of the buttons function and the only light lit is the power light. The only way I can stop it is to disconnect it from the mains supply. Can anyone help me please?