how can I fix my indesit washing machine?

I have an Indesit W123 washing machine which is approx 5 years old.The main programme selector on the right hand side of the control panel as you face the machine goes round and round when a programme is selected for washing.It makes a ticking noise as it goes round and the only way to stop it is to press the main on/off button on the control panel.Is this terminal or would it be worth buying the appropriate part and undertaking the repair myself,I am very competant at this sort of thing.Many thanks for any help/advice on this matter.Regards AL.