I know this might sound daft Saaf but ask her if she has any wireless phone systems in the house. Had a Dell laptop the other week that wouldn`t connect when one of the wireless phones was nearby.
Probably nothing to do with that though judging by what i read here
http://www.mobile-phones-uk.org.uk/3...-broadband.htm
There`s a bit where you can put your postcode in.
Maybe it`s connected enough to ping but as soon as anything substantial is asked for it borks!