|Does your XP laptop have a wifi adapter? Does the adapter work?|
Assuming the answer to both is yes, you need to run the wifi software, have it scan for WLAN's and then connect to whichever one you want to. If the WLAN is secured, you'll need to know the encryption key so you can enter it when asked.
Once you've connected to a WLAN, the profile for it should be saved and when you reconnect in the future, you shouldn't have to enter the key again.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.