The flashing lights are indicating a fault in the heating circuit.
You will need to have, and be able to use, a multimeter to narrow the fault down.
You would need to check the heating element, it should be around 30 ohms.
Check pressure switch connections (contacts 11 - 14)
Check wiring and connectors to and from Main PCB; heating element and pressure switch
l If all the above checks out ok, you'll likely need to have the main control board replaced and programmed to your appliance.
If you are unable to do the checks then you would be looking at replacing parts on a "fit and see what happens" basis. This could work out extremely expensive.
If the main board is to be replaced and programmed then the most cost effective repair would be to have Hotpoint come in and repair the appliance on their fixed price repair scheme (same price as the 5 year parts warranty).
You need to call them for their latest prices and schemes, they all include parts and labour.
Sorry it's not good news or an easy fix.
Let me know what you find.
Hope this is of some help