Your username and password should be the one supplied by wanadoo and the same as you usually connect with via your modem, I would always choose a manual reset over a software one, when you do reset it go into the 10.0.0.2 page and see if it has actually changed anything to make sure that it has actually reset it.
I have just come across this while looking for solutions to your problem :
You need to find outy how to register with your ISP. First I would unplug the power to both the modem and the router, leave them sit for a minute or two and then plug them back in one by one starting with the modem. If the router still obtains a 0.0.0.0 address let us know.
<<<an ping all the pc's and open shared folders etc. and ping the bt server on 194.72.9.34 but cannot get to the internet.>>>
This is normal issue for ISPs who require equipment to be registered to get an IP it is referred to as a walled garden. It allows registered devices in but blocks internet access to restrictde, unregistered devices. First find out how to register from BT if you are not automatically taken there.
I have heard of cable ISPs needing to have equipment registered before but not ADSL ones. It may be worth giving wanadoo a call t osee if this is the problem as the IP should be automatically provided to your router as soon as the ADSL link makes the connection.
Has anyone else come across the need to do this on ADSL