Cannot access particular URL

Looking for guidance here as I accept this may not be an IE issue. I have a
home network connecting through a DLink router to ADSL. All worked fne until
today (and no known changes made). Now I cannot access any part of the BA
website (www.britishairways.com or www.ba.com) as I get the "page
unavailable" screen. BUT - the website is working as I can access through a
dial up via a non-networked laptop and I get the same error on all PCs on the
network. All other websites that I try are fine so I am trying to think of a
(probably) router error that would effectively block just one site..!! I
have rebooted the router. I shall of course seek guidance on a Dlink forum
but hoped someone here might also be able to help