It can only revert to a dial-up connection if the PC has got a dial-up modem which in turn is connected to a normal telephone line using the correct cable. You can't get a dial-up connection through a broadband modem - one's analogue and the other is digital.
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.