SONY VAIO VGN-FE11M wireless connection problem

Hi
I just purchases a brand new sony vaio fe11m laptop which is supposed to be a high spec machine but I cannot get the laptop to connect to my wireless network using it's internal wireless card.

I have a UK Wanadoo live box router.
The livebox has picked up the device address of the sony wireless card.
I have entered the correct WEP key in sony wireless set up.
My network appears in my wireless networks list.
It seems to connect to wireless network but then gets stuck acquiring a network address and is never able to get an address from the router.
I am using norton internet security 2006 which I have disabled and it still does not work.
I have scanned through this forum and can see that other people have had the problem. My old sony vaio laptop is able to connect to my router using an external network card so I know its not the router.
I have contacted Sony and Wanadoo who have been no help whatsoever.
Any ideas ?