Error 720 : Windows XP

I've recently installed a Nildram ADSL modem into my mum's Dell machine. Now that connection, any other dial-up connections I had and any new connections I install have the same problem.

I get 'Error 720 : A connection to the remote computer could not be established. You might need to change the network settings for this connection.' When I click on more info it says, 'A connection could not be established because the Point to Point Protocol (PPP) settings on your computer and on the remote computer do not match.'

A few other points :
Do you need a network card installed? I've installed a card because I thought it might be needed. I might try it without the card installed, but if you need the card then it would be pointless to try this.

I've installed and uninstalled the modem and network card a large number of times.

The phone line is fine because I'm able to use a laptop modem in the phone socket.

I've ran out of ideas and I've talked to Nildram who couldn't help me. I've also tried System Restore.

Is there a way of unistalling and then reinstalling Dial Up Networking under XP as I think this could be the problem (although I don't think you can do this). Perhaps there's a way to reset TCP/IP?

The final hope might be to completely reinstall Windows but I only want to try that as a last resort.

Dave Besag