Web browsing issues after installing windows

I've just installed Windows xp using bootcamp on my macbook, and am experiencing issues accessing certain websites using both safari and mozilla. I'm given a 'problem loading page' message when attempting to access sites that were perfectly acessable yesterday and are still acessble on my housemate's pc now.
I'm using a direct connection (ethernet) and am networked along with 2 pcs in my house through a router.

Am wondering if it may be a firewall issue that I'm unaware of, or perhaps an installation of windows- related stuff up. I'm new to macs so I'm lost for ideas.
Any help is much appreciated