My laptop is a Dell 1705, which is very much like yours. Recently I installed XP again, but a slightly different version. It was a Dell windows XP disc, but for some reason did not have all the drivers for this laptop.
Going to the Dell website, and using my service tag number, I was able to locate the driver set. But even then it took awhile to find the exact drivers in the set. Maybe you have a problem like that.
But one other thing. Is the Wi-Fi light on? On my laptop it turns on or off with Fn F2. Check your keyboard and find the little thing that looks a radio tower.