That is complete nonsense, there is no way to erase an ecu memory that is more likely to damage it if there is any residual voltage left in the capacitors within the ecu, I suggest anything you do now is just causing more problems, it my be time to call in the professionals. Sorry to be brutal but MGF is a fairly modern car and the old ways of flashing alternator/ dynamos have long gone, to check faults now you really need diagnostic tools.