XP Vista Crossovercable LAN

i have a laptop dell insprion 1100 laptop with windows XP professional, and a custom built desktop with windows vista ultimate 64bit

when i plug it in it has error saying that i have same ip so i changed the ip and subnet to what ive read on the internet, however it will not connect, i can see my vista computer on my laptop but i cannot see the xp through vista

please help?

cheers