Strange issue. Try booting into safe mode and see if they work. If they do not, I suspect that it may be an issue with the keyboard hardware, i.e. the strip connecting the keyboard to the motherboard may be shot. You can try taking the keyboard off to see if there is anything amiss underneath it in regard to the strip/cable.
Many thanks for the info, those keys dont seem to work in safe mode either!!!! will try to get to keyboard to check - if not it will go back to the shop.