To properly secure your home wireless network, you must enable wireless security. You can choose either WPA (recommended), WEP 128-bit, or WEP 64-bit security. The same type of security must be used by your wireless router and all the PCs connected to your wireless network. The security scheme then assigns an encrypted network key to your network; each PC on your network signs in using this key.
You can assign network keys to all the PCs in your network in one of several ways. Most wireless hubs, routers, and adapters come with configuration utilities that let you activate this type of wireless security. If your wireless equipment has this type of configuration utility, use it.
Otherwise, you can use Windows XP's Wireless Network Setup Wizard to manually assign network keys to each computer on your home network. Despite the name, you don't use this wizard to actually set up your wireless network. Instead, its purpose is to add security to your already installed wireless network.