Can't connect to internet through wireless router

I have a laptop that's running Windows XP. I can connect to the internet through my home router with no problem. I gave this computer to my daughter to use at her house. When she tried to connect to the internet through her wireless router it wouldn't work. I have made several attempts to establish a connection for her through her router, with no luck. (to say I'm frustrated is an understatement) My SSID is different from hers, which I think is the problem. How do I go about doing this manually? I've run the network setup wizard several times, but it doesn't keep my the SSID I try to change it to. Thanks for your help!