Wireless internet help

I recently installed Windows XP on my macbook using BootCamp. I can connect to the internet (at home, using a router) while using Mac OS X 10.5, but as soon as I switch to XP, a little notification tells me I have 'limited or no connectivity'.

So have I accidentally missed a step while setting up XP? I've installed the necessary drivers too, so I'm certain that's not the problem.

Any help is GREATLY appreciated!

NOTE: I can connect to my university's wireless network using a VPN in XP and Leopard, if that helps in diagnosing the above problem

 

Nobody?