If I had to guess I'd say it was something with XP's wireless driver but again I can't say for sure. Were you ever able to connect to that AP with this laptop wirelessly? Can you get internet with a cable(wired directly to it)? If you can get the net wired but not wireless then it is completely in the wireless drivers. If you can't get it either way then you have a problem with the TCP/IP software on the computer and I am completely clueless as to how to fix that

Either way its related to the software...I always end up just reformatting when it gets screwy like that since there is no cheap way to solve that problem. I have never had any hardcore geeks around when I needed them or didn't have the right currency to hire them...computer hardware, cash, Twinkies...whatever:-) Try the troubleshooting above and maybe we can fall on a solution, or at least know where the problem may be.