When using a wireless network on my school campus, I compare my Mac Book and my brother's iBook. Both have factory installed airport cards. We both have strong signals coming to our comps, but the difference is that his internet works on the iBook and my internet doesn't seem to be connected, even though I'm getting a strong signal from the network. Does anyone know what the problem is? Is it possible it's a hardware issue with my AirPort card or even my computer?