The most likely fault would be the door lock has failed.
When you close the door and try to start the appliance, does the door actually lock?
This would suggest that either the door lock or the main control board is faulty.
Unplug the machine.
To test the door lock you could bypass it by linking connections 3 and 4 together on the door lock plug. (The door lock should have the numbers 2, 3 and 4 marked on it, match these to the plug and link out 3 and 4 on the plug to test the appliance).
Fit everything back in place with the link on the plug insulated.
Plug the machine in and try it again.
If the machine then still does the same, the pcb will need replacing and programming.
Hope this helps
Let me know how it goes or if you need more help
I'm not in the office now so don't have the diagram at the moment.
Put the plug in and match the wires to 3 and 4.
If your plug is 1 to 2, 2 to 3 and 3 to 4 then it's 2 and 3 to link.
The diagram shows 3 and 4 are linked together when the door is closed.
Put the door lock back the way it was.
It looks like the main control board (pcb or module) is going to be at fault.
This will need programming to your appliance.
I would suggest trying a new door lock first.
If the lock doesn't fix it, then I'd suggest getting Hotpoint to come and repair it on their fixed price, parts and labour, scheme.
The cost will be lower than the cost of buying a new pcb, a programmer and a smart card with the programme for the pcb.
Sorry it's not good news.
Good luck with it.
Hope this is of some help