I'm not an official helper here but I have just cured this problem by resetting my router to factory defaults. I think the "use this DNS address" had been selected and set to do this. I reset to "use ISP's DNS".
Thanks to all the full time helpers I have learned a lot reading your replies.
Hope I'm not out of order for jumping in here.
Edited by 747skipper, 21 June 2010 - 05:33 AM.