[H] wireless problems

[Winterlight]

I am working with a Dell 700M that has onboard Intel 2915abg wireless 
adaptor. I am having a problem getting a connection to my 
router.  There is nothing wrong with my wireless router, I have one 
laptop continuously connected, and a desktop and another  laptop 
connecting just fine. The wired LAN port on the Dell works perfectly 
in the same router.

The Intel 2915abg sees the router accepts the WPA key and then times 
out Acquiring a  Network Address. . I have tried turning off the XP 
firewall, I have removed and reinstalled the adaptor, I have been 
able to get a connection for a few minutes but it looses it right 
away. Signal strength is excellent. Something is preventing a 
connection at the end of the connection process. Any ideas?

thanks