Can you post the make and model number please.
I dont suppose you have a model number do you?
If not then is it an induction hob?
if so is one side working ok still is it just one half you are having problems with?
Is it an induction hob?
Have you just installed it or have you had it a while?
Is it an induction hob or a normal ceramic hob were the heater plats glow red?
As induction hobs you need stainless steel pans and it works as magnetic coils. To be honest dont think it is as you would have known if it was induction as the heater plates dont glow red.
But as to the fault if its switching itself off then its either the mains connection block under the hob were the power cable goes to or the main control board.
If checking this yourself you need to remove the hob from the worktop and turn it over.
There you will see the connection box were the power cable goes to. Open this up and check for signs of burning on there. If so then you need to replace that.
But if thats fine then its more then likely the main control board as thes hobs are electronic controled so for the fault you have the power board will need to be replaced.
But this is a very expensive repair and given its 5 years old its may be cheaper to get a new hob rather then fixing this as boards can be £200+
If you need anymore info just get back to me.
Ok if it glows red then its just a standered ceramic hob rather the induction.
If you get some one to check the wiring to the hob and the connection box an then you can rule that out.
Then it would be a case of either replace the control board or get a new hob. Thats up to yourself on this.
But if you need anymore info or help on this just get back to me. You can still reply to me even after rating the answer so if you could remember to click the star ratings that would be great.