ok what you need to do is goto control panel internet options then connections. Double click on the default connection and make note of the dial up number your username and password(you should know these)
on new pc same place at the top select set up new connection follow the wizard until it says set up connection manually add the information you require and at the end tick make a short cut to desktop.to connect to the net simply click this shortcut and hit connect
Or you could goto isp web page and see if they have the option to download a small file with this information